So why listen to me? What makes me an expert on Io?
I have 10,000+ matches played in Dota 2, totaling 9000+ hours. Of those ~10k matches, ~3500 of them have been with Io. This means I have spent more than a third of my Dota 2 experience playing Io.
I maintain a >58% Io win rate, which is almost 20% above the global average.
I also manage a small Youtube channel and Twitch channel dedicated solely to Io gameplay.
I have spoken with some of the best Io players in the world as listed on Dotabuff (‘Ziqi’, ‘N-R-C’, ‘Mikushiru’, ‘Pardon My Trench’, ‘Guardian/Wisp’, ‘Hachi’) to understand their logic and strategy when playing the hero.
*Update 1/2018: I am currently ranked Top 100 on Dotabuff Io Player Rankings.
*Update 2/2019: The in-game version of this guide is ranked as the #1 Io Guide in Dota 2.
Trust me when I say, I am borderline obsessed with this hero and its complexities (of which there are many). Let my addiction fuel your education.
I apologize in advance for the length of this guide. Io is very complex hero, and that complexity extends to how each individual skill can be used. That being said, if you play Io, and you want to get better with the hero, I guarantee that you will learn something new from this guide.
*Update 10/2017: This guide won the DotaFire 2017 Guide Contest in the Strength Hero Category!
Most Recent Updates – 7.21
Io can be played as a melee DPS hero now – who knew? Thanks new Overcharge!
Maxing Overcharge before Tether in combination with your Lv10 +45 Damage talent means Io has a strong mid-game fight impact. Old Overcharge had a variety of negatives that had to be weighed accordingly against the positives and required a high level of finesse to use properly. The new Overcharge is easy as ****, has no downsides, and is powerful as ****.
Items (Core) – Soul Ring Build
“Soul Ring Build” is a subtype of Io itemization that I often play with. It avoids Bottle and instead relies on Soul Ring for non-Rune-based MP regen and better passive HP regen. The items described below are my personal core Soul Ring Build items.
Tangos heal you for 7 HP/sec, and heal your Tethered teammate for 10.5 HP/sec. Tangos last for 16 seconds, so try to make sure you’re Tethered for most/all of the duration.
Gauntlets of Strength
+3 Strength helps support Io’s HP as well as his opening harass/deny damage, while also building into Soul Ring very early in the game.
Healing Salve heals 400 HP over 8 seconds, at a rate of 50 HP/sec. This becomes 75 HP/sec through Tether, and can be used to win teammates, save allies, and keep Io alive in crucial situations. This item is NOT to be underestimated.
Mango increases passive healing by +0.6 HP/sec, improving casual Tether healing even further and reducing pressure to use consumable regen. Consume Mango to secure an early kill by gaining 125 MP and 188 MP for your Tethered Ally.
This will help to replenish mana spent in the first few minutes of the game, from Tether and potentially early Spirits casts. Tethering to a teammate will give them explosive mana gain.
Courier is an EZ way to support the team that will make your teammates happy. If already purchased, buy a ward instead.
Because this build lacks Bottle (and the early healing that comes with it), Io spends heavily on consumable regen items to help support his carry’s HP.
(1) Soul Ring
Soul Ring is a more stable mana-replacement item than Bottle. With this item, you can generate 150 MP every 25 seconds for yourself, which is 158 MP for your Tethered partner (225 MP at Lv4 Tether). You must spend the 150 MP before the Soul Ring buff ends (10 seconds), but your Tether partner is not effected by this rule. Through this method, Soul Ring can generate up to 900 MP in under 2 mins [225 * 4 Soul Ring uses] for your Tether buddy.
Soul Ring is best combined with low-mana carry heroes that have short-cooldown stuns or damage spells. Sven, Luna, Chaos Knight, Legion Commander, Bristleback, Phantom Lancer, Necrophos, Pudge, Tiny, Wraith King are good examples.
The 150 MP from Soul Ring is also exactly the cost of a Spirits cast. Therefore, Soul Ring is best used by (1) Tether to target (2) use Soul Ring, giving you 150 MP and partner >160 MP (3) cast Spirits for 150 MP, losing 0 net mana. Buying Soul Ring allows Io a far greater freedom to use Spirits, Io’s main damage spell, at a high frequency compared to other early game items such as Bottle.
Soul Ring includes +6 Strength (+135 HP, +6 damage, +0.75 HP/sec, 0.6% status resist), which increases Io’s ability to last hit and harass effectively. Soul Ring also increases your passive HP regen/sec by +2.5. However, because of the changes to the way HP regen is calculated, Soul Ring gives over +3 HP/sec regen.
Another minor use of Soul Ring is to lower your HP – on purpose – in order to passively heal a Tether target. Normally Io’s health is lowered with Overcharge, but this is an extremely inefficient way of doing so because of the large amount of MP lost relative to HP. Using Soul Ring instead is far more constructive to your mana pool.
(2) Magic Wand
Magic Wand helps to improve Io’s passive HP regen alongside Soul Ring, while also providing a much-needed stat boost and a quick-activation healing item which can be used while Tethering to a target. At 10 charges, a Wand heals for [15*10=] 150 HP/MP for you and 225 HP/MP for your Tether target, which is almost the strength of a Mekansm charge. At 20 charges, it’s 300 HP/MP for you and 450 HP/MP for your Tether target.
(3) Urn of Shadows
Urn of Shadows provides more stats (and armor, importantly) for Io survival, but the real profit comes from the use of the Urn charges. Urning yourself heals for 30 HP/sec over 8 seconds, which is weaker than Bottle healing (which is 50 HP/sec) but lasts far longer (8 sec vs 2.5, 400 total healing vs 125). When Tethered (and Overcharging if required), this heals your Tether target for [30*1.5=] 45 HP/sec. This makes Urn a powerful healing spell that is crucial to Io’s mid-game healing functionality.
Urning enemy players deals 25 HP/sec in damage, and its long range can net you crucial kills and can help increase your DPS in teamfights.
Because of this, Io should have priority on the team to purchase Urn of Shadows over other heroes who normally have Urn in their item builds (such as Huskar, Pudge, or Spirit Breaker).
Items – Speed n’ Spirits (Damage Build)
“Speed n’ Spirits” is a damage build designed to maximize the Io’s speed and the damage output of Spirits. This build starts from a SOUL RING BUILD base.
Helm of the Dominator – 1875 gold
Io needs passive HP regen in order to maintain his reliance on Soul Ring for Spirits casts, as well as save his Urn of Shadows charges for combat scenarios. Helm of the Dominator provides an amazing HP regen buff for Io and his allies, which gives Io and all his allies 8.5 HP/sec in a AOE, and increases Tether regen strength by [8.5+(8.5*1.5)=] 21.25 HP/sec!!!
HoD also provides Io to dominate a creep, which can be used to give passive bonuses (which are stronger the earlier you get them) and also act as a Tether target. Tethering a dominated creep (who’s speed is set to 425) gives Io an IMMENSE speed increase from his base of 285 to almost 450 (~485 with Lv4 Tether). This heavily complements Io’s initiation and escape abilities and allows you more right-click attacks and an easy opportunity to slow down escaping enemies with your Spirits. Not to mention, the creep is still controllable after Io’s death, meaning you can still net last hits and even kills after your death.
In the late endgame, if Io is 6-slotted and needs another item, HoD can be used to dominate a creep and then be placed in the Backpack while the domination continues, freeing up an item slot while still providing movement speed + neutral creep bonuses.
Medallion of Courage – 1175 gold
Before 7.07, I would get my armor from the Lv 10 Talent and build Glimmer Cape for survival. Now that the Lv 10 Talent has been changed, Io must find his much-needed armor boost from items instead.
Medallion of Courage provides +7 Armor and 0.75 MP/regen, but more importantly, it allows you to utilize your aggressively fast movement speed to chase down enemy opponents and strip armor off of them as they retreat. It can also be used in teamfights when Io is not being focused – which will be difficult when he moves so quickly.
Cheap, effective, and even more deadly due to Io’s movespeed, this item builds into the even more devastating Solar Crest later in the game.
Veil of Discord – 2050 gold
Veil of Discord provides +6 Armor, as well as +6 HP/sec, +6 Strength, +6 Agility, and +14 Intelligence. This is an incredibly well-rounded item for Io, who at this point has a small mana pool which is greatly increased by Intelligence (+168 MP total), low total armor which is greatly boosted by +6, and who could always use more HP regen to help heal others. Veil of Discord is also 250 gold cheaper in 7.20 compared to previous patches.
Veil of Discord activation, which reduces Magic Resistance by 25% for enemies in a 600 unit AOE, also combos very well with the new Lv15 Talent that provides +75 Spirits damage. The total damage figures are presented below:
80 damage * 0.75 Magic Resistance = 60 damage per orb
Spirits + Lv15 Talent =
155 damage * 0.75 Magic Resistance = 116.25 damage per orb
Spirits + Lv 15 Talent + Veil of Discord debuff =
155 damage * 0.75 Magic Resistance * 1.25 Veil debuff = 145.31 damage per orb
Veil increases your 116.25 damage by an additional 29 points per orb, or approximately 150 damage (after resistances are factored in) per cast! With Lv 15 Talent and Veil of Discord, Spirits hit for 145.3 * 5 = 726.5 life points worth of damage, as compared to 581.25 damage per cast without Veil of Discord.
Do not forget that increasing your Intelligence increases your bonus Magic Damage. All of the above numbers could be increased from 1-7% depending upon how much Intelligence is in your item build (Veil’s +14 Intelligence alone provides +1% Magic Damage), meaning your [Lv 15 + Veil] Spirits cast of 726.5 damage could actually be hitting as high as 775 damage…
Veil also combos with Urn of Shadows / Spirit Vessel, as the damage type from activating those items has been changed from Pure to Magic.
Solar Crest – 2700 gold upgrade
Solar Crest is a great item to influence the amount of killing potential Io has alongside his Tether partner, while also providing physical defense for Io. Solar Crest can be used both offensively and defensively – it increases Io’s sustainability when attacked by other heroes, and can also be cast on the Tethered ally to temporarily give him bonus evasion and armor as you heal in the background. Offensively, Solar Crest can be used on an enemy hero to decrease their armor/evasion and help your Tethered ally kill them faster.
Desolator – 3500 gold
Deso combos incredibly well with both Lv25 Talents. The Lv25 Attack/Tether Talent can be used to rapidly push down towers and barracks in short time frames, while the Lv25 30s Relo Talent allows Io to relentlessly push towers while lowering tower armor for his Tethered Ally. Deso opens up the amount of building damage you can do within one 12-second Relocate, and regardless of your Lv25 talent choice, this item can help you end games.
Deso can also impact teamfights alongside the Lv25 Tether/Attack talent via Tethering to fast-attacking or multi-shot allies and stripping armor from multiple enemy heroes at once. It combos especially well with Solar Crest, where the combined items can remove 19 armor from a single target.
DAMAGE BUILD – ENDGAME ITEMS
Heart of Tarrasque – 5200 gold
If you can get your hands on this item, the game is borderline over. By staying behind your team’s lines and Tether/Overcharging heroes taking damage as you heal 5% of your max HP per second, you can swing teamfights in your favor, support pushes by recharging half-health heroes, and even tank tower damage without flinching. Not to mention the 50% increase to ALL of Io’s passive HP regen (including HoT itself) IN COMBINATION with Holy Locket, Io is a ******* healing machine.
Tether healing with HoT heals your target for upwards of 400 HP/sec, and that’s limited because OVERCHARGE DOESN’T TAKE AWAY HP FAST ENOUGH (Overcharge bleeds 6% HP/sec, HoT heals you 5% HP/sec + 50%). If you are damaged and can heal at the full rate HoT allows, you will be healing a Tether target for upwards of 700 HP/sec. Greater than 1 Mekansm activation PER SECOND. That’s how f*ckin insane this item is.
Support Items – All Builds
SUPPORT ITEMS AND CONSUMABLES
Support items are match-dependent, item build-dependent, gameplay style-dependent – as a result, they will change wildly from player to player and game to game. That being said, below are notes about the most important support items and consumables for Io.
Tome of Knowledge
Tome of Knowledge is really important for Io because his talents are both powerful and cumulative. The earlier you get Lv 10, the earlier your +25% XP talent can start working for you. The sooner you get to Lv 20, the sooner your +150 GPM talent can start working for you. Great item, purchase it when you can.
Town Portal Scroll
Using the TP scroll can save your life by escaping bad situations, but it can also allow Io a quick rotation to help another teammate stay alive or secure a kill. TP scrolls can also be used in combination with Tether as described in the “How to Use Tether: Intermediate” section of this guide. I have one, if not two TP’s in my inventory from minute 10 until the end of the game.
Observer Ward/ Sentry Ward
Wards are important for granting vision into the enemy’s half of the map. They allow you to know where an enemy is, and this information can be used to move around the map and farm lanes/neutral camps in a safer fashion. I feel that in the early game, a good team who is vocal about missing calls can accomplish the same effect as having wards, and as a result, I tend not to purchase wards until the mid or late game. When I do buy them, I’m aiming to plant them in the enemy jungling areas (or any raised structure with an “eye” painted on it). I feel wards are most effective in the later stages of the game to allow your team to coordinate difficult ganks, push T2 or T3 towers, fight Roshan, and other multi-player movements that are safer to accomplish when you can see the position of 2-3 enemies on the map.
DO NOT BE HARASSED into buying wards or any other support item. If your teammates cannot play without constant map vision, then they are bad, and that is not your financial problem. Tell them how much wards cost and where to buy them.
Dust of Appearance
“Dust pays for itself” – that is my motto. Dust is big for later-game Io Relocate ganks onto heroes that rely on invisibility items or spells to escape, such as Invoker, Shadow Fiend, Riki, Treant Protector, and Tusk, just to name a few (with the exception of Weaver, who can ult to remove Dust debuff). Dust is more reliable than Sentry Wards in my opinion and physically slows invisible opponents, making them easier to kill.
Raindrops are an optional item for Io that I would purchase if I felt I was being pressured by enemy magic heroes. Raindrops add a lot to Io’s survivability at the early/mid stages of the game, and the passive MP regen is a nice bonus for you and your Tether target.
Smoke of Deceit
While I don’t do this nearly often enough myself, Io should have the money in the later stages of the game to buy Smoke so that his team can successfully gank the enemy side of the map. 50 gold in exchange for a great kill set-up is absolutely worth the price.
Skills and Leveling Up
Wanna skip reading this section? Well then this is all you need:
(1) At lv 5, your skills should be 1-3-1
(2) Finish maxing Spirits first
(3) If you want to be more aggressive, max Overcharge
(4) If you want to be more supportive, max Tether
Io’s skill build is relatively standardized.
There are differences of opinion about what skills to increase on Lvs 2-4, but the controversy is very minor. Bottle Build players might prefer an early point in Overcharge at Io Lv 2 to utilize Bottle healing on their carry, where as Soul Ring Build players might level up Spirits early (and ignore Overcharge until Io Lv 4) to put the mana output from Soul Ring into a higher-damaging spell.
By the time you’re Lv 5, your skill build should be 1-3-1. You can take whatever path you’d like to get there, but as long as you’re leveling up Spirits first and have 1 point in Tether and 1 point in Overcharge at Io Lv 5, you’re doing fine.
If you’re lv 5, and your build is NOT 1-3-1, you’re doing it wrong. 100%, no questions asked, completely, utterly, wrong. I’m sure this statement will upset SOMEONE when they read it, but it’s the unfortunate truth. You can watch any professional Io game from the last 18 months and every single player maxes Spirits first.
Why rush Spirits first, as compared to Overcharge or Tether???
Spirits is Io’s bread and butter. Lv 4 Spirits provides 400 magic damage (5 orbs x 80 damage) on a 20-sec CD.
Leveling up Spirits increases the damage of the orbs by the same amount at every level. It is a 100% increase in strength per level. 1st level is 20 damage per orb. 2nd level is DOUBLE that. 3rd level is TRIPLE that. 4th level is QUADRUPLE that. That is a 400% increase over 4 levels.
Leveling up Overcharge only increases the Attack Speed stat by 25% of the original per level (Lv 1 = 40, Lv 2 = 50, Lv 3 = 60, Lv 4 = 70). That is a 75% increase to Attack Speed over 4 levels (vs 400% if you leveled Spirits). The damage block DOES quadruple in strength like Spirits damage (5-10-15-20), but this does not get you kills in the early game and only improves defense. Even if you are supporting a carry who benefits from the Attack Speed and Damage Reduction bonuses, you are still doing yourself a disservice by not investing in your most powerful spell, Spirits.
And don’t get me started on leveling up Tether…it works very well in the mid-game to increase your healing and mobility, but without damage behind it, you are just a moving target for your enemies.
If I see another Russian youtuber put 3 points in Tether by lv 5, I will scream.
How to Use Tether
Tether allows you to heal a teammate by 1.05x your MP and HP regen, up to 1.5x at Lv4. If you are healing for 20 HP/sec, your target will be healed for 30 HP/sec.
IF YOU ARE NOT GAINING HP OR MP, YOUR TARGET IS NOT GAINING HP OR MP. If you heal yourself while you’re at 100% HP, and do not physically gain any new HP points, then your target will not receive them either. Overcharging to lower your health <99%, or taking damage, or using Soul Ring are all ways to ensure this does not happen. This is less of an issue with MP regen, because the act of casting Tether on a target is enough to lower your MP below 100% (paying the 40 MP cost to cast Tether) so that your Tether target is basically guaranteed some level of MP regen.
Urn of Shadows, Magic Wand, Bottle, and Mekansm are active ways of healing yourself to help heal others. Tranquil Boots, Hood of Defiance, Heart of Tarrasque, and other passive heals (such as activated Fountains) are also viable options for healing (and often overlooked).
(2) Speed “Adoption”
Patch 7.13 – Your movement speed matches the movement speed of your Tether target. Io starts the game with 285 movespeed, and gains great advantage by Tethering to his allies who purchase Brown Boots in the early game. Agility heroes will naturally gain speed at faster rates than other allies, so they tend to make great Tether targets.
This can be abused in some ways. If Io is slowed by a spell or ability, but his Tether target is not, IO WILL NOT BE SLOWED. This means careful re-Tethering in a fight from a slowed target to a non-slowed one can keep Io’s movespeed unchallenged.
Be careful about Tethering in to help allies. If an Ally is slowed by spells/abilities or is a naturally slow-moving hero, it will be difficult for Io to escape with that hero, even with the 5-14% speed boost. Io must consider the risks of Tethering to a slow ally.
This change to Tether is why Helm of the Dominator is such an important item in the Damage Build. Tethering to a dominated creep (where the item sets this creep’s movespeed to 425) means Io moves at [425*1.05=] 446 movespeed, which is an incredible gain over his natural speed of 285.
(3) Speed Boost
Tether gives your target a 5-14% speed boost, which increases the speed you are moving by extension. This is useful for chasing enemy heroes or for running away from ganks. It can be cast on creeps as well.
(4) Pulling Effect
If Io Tethers to a target that is 700 or more units away (out of potential Tether range of 1800 units) then Io will be “pulled” to that target. This can help Io escape pressure from enemy heroes and improve his positioning.
This is especially effective when used to Tether up or down cliffs, where enemy heroes cannot directly follow.
A great example of this is when you are hooked by a Pudge. Unless the Pudge has a very quick hand, you should be able to Tether directly back to safety by targeting a nearby creep or teammate BEFORE Pudge can activate Dismember.
(5) Fight Initiation/”closing the distance”
Once Spirits has been leveled to max, the “pull effect” of Tether can be used to attack enemy heroes by approaching them faster than they can respond, especially in the laning phase. If you walk up to an enemy hero with your Spirits activate, most players will tend to back away from the spinning orbs, or perhaps attack you because they think you are a weak Io. By tethering to a friendly creep that the enemy hero is trying to farm (while you have Spirits active), you can pressure the enemy hero with physical attacks and Spirit damage (and possibly Urn damage, too). This is a great initiation route for getting kills in the earlier part of the game.
(6) Assisting your Teleport
Much like Teleporting during Storm Spirit Ball Lightning, Io can Teleport (using a TP scroll) during the “pull effect” movement of a recent Tether. First cast Tether on a far away creep or hero, and then immediately activate the TP scroll as Io is “pulling” towards his Tether target. This can increase the distance between you and an enemy hero with a stun or disruption, and can buy you valuable seconds for the TP cast to finish.
(7) Tethering Invisible Heroes
When Io Tether’s an allied hero that then turns invisible, the enemy sees a “fake Tether” that links between Io and the last visible location of the invs hero. If the invs ally moves, his Tether “link” will not, confusing the enemy and hiding his true position. If you approach an enemy from offscreen while Tethered to an invs hero, the fake Tether will look as if it extends offscreen behind Io. This can be used to your advantage to confuse enemies, because Tether acts normally in every scenario except for this.
Your allied hero still gains all the benefits from Tether including movespeed buffs and healing, meaning invs heroes like Bounty Hunter, Weaver, Riki, or anyone with a Shadow Blade make excellent ganking partners alongside Io, who can Tether to them without giving away their position.
(8) Tree Removal
Io’s Tether is useful for destroying large areas of trees. This is especially helpful in the early laning stages, where enemy support heroes will tend to harass carries from behind a treeline (for instance, Radiant safelane carry being harassed by Dire heroes from the Western treeline). By Tethering to a creep or hero from far enough away that the “pull effect” occurs, wherever Io stops/slows from the “pull effect” will have an area of trees destroyed around it. This is designed so Io does not Tether to save someone, but gets himself caught in the trees and unable to escape. By intentionally cancelling your Tether over a collection of trees, Io can maneuver himself to cut down trees faster than some Timbersaws.
This can be used to your advantage to destroy trees where you think enemy heroes will want to stand and harass you or your carry. The Radiant safelane Western treeline is one example. Another would be the Dire safelane trees that are just below their Tier 1 tower – removing these provides a greater avenues for harassing opponents and paths of initiation. Clearing trees in your own jungle to assist with neutral stacking is a viable option as well.
(9) Creep Block
This is a minor use of Tether, but one that I don’t see performed very often. In the first 30 seconds of the game, players should be attempting to body-block the first creep wave. If Io makes a mistake in the first few seconds and lets a creep slip past, he is able to Tether ahead to his lane partner in order reposition himself ahead of that creep and have a 2nd chance to block effectively.
(10) Creep Boost
Another minor use of Tether is to Tether the ranged creep of the first creep wave that spawns at 0:00. Tether provides the ranged creep with a 5% speed boost, which will hopefully increase the chances of it overtaking the other creeps in the wave and reaching the enemy creep wave first. This means your ranged creep will be taking damage before the enemy ranged creep, and because ranged creeps are a major pushing agent, its early death will ensure that lane equilibrium is pushing in your favor. It also primes the ranged creep to be denied, which is key for denying the enemy heroes early XP and gold.
How to Use Spirits
Spirits is a vastly underestimated spell. At Spirits Lv 4 (which you should have at Io Level 7), the spell provides 400 magic damage (5 orbs x 80 damage each) which is strong for a Lv 7 support hero.
The orbs can be expanded and contracted, and the range of these orbs is amazing for netting Io kills that other heroes do not have the range to finish themselves.
There is very rudimentary advice I can give about getting better with Spirits expansion/contraction. Practice makes perfect. Practice practice practice.
(1) If you are chasing an enemy, EXPAND orbs.
(2) If you are about to be charged/stunned/dueled, CONTRACT orbs.
(3) Your range is better than their range.
(4) Aim for groups of heroes.
These orbs also have an AOE component, which means that when enemy heroes are grouped up, hitting one of them with orbs will damage multiple heroes. So not only can Io throw out 400 magic damage in a very short period of time, but he actually cause MORE than 400 magic damage by hitting heroes who are close together. Keep an eye out for this setup.
Spirits impart a 20%/40%/60%/80% slow for 0.3 seconds upon explosion. This totals 1.5 seconds of 80% slow at Lv4, meaning Spirits can be used to help Io and his Tether partner catch up to escaping enemies.
(4) Overlap Theory <– This is f*cking important
“Overlap theory” is the idea that the floating orbs of Spirits last for 19 seconds, but the cooldown for the spell (at lv 4) is only 14 seconds. There is a 5 second “overlap window” whereby Spirits is active, but can also be re-cast as a new spell.
This allows Io to engage in a fight whereby he already has Spirits active, can use those Spirits to cause 400 magic damage to a target, and then IMMEDIATELY cast Spirits again, causing ANOTHER 400 MAGIC DAMAGE to a target. This series of events can take place over several seconds and is CRUCIAL to Io getting kills and rapidly increasing his DPS in fights. 800 magic damage is almost a LEVEL 18 LINA ULTIMATE.
You’re a lv 7 Io.
Let that sink in for a second.
If you activate Spirits early enough before a fight occurs, you can cause 800 magic damage with Spirits alone. Not to mention your physical attacks (with or without Overcharge boost) and damage from Urn of Shadows. Combined with a fast initiation, this technique makes Io a f*cking deadly hero.
Overlap theory was first butchered in 7.14, and then totally destroyed in 7.19 and 7.20. I am leaving this section of the guide up as a rememberance to when Io’s damage capabilities were powerful, dynamic, and actually took skill to use properly.
Spirits can provide vision to Io in multiple ways. First off, if a Spirit hits a enemy hero, that hero is visible for several seconds. NO ONE SEEMS TO REALIZE THIS. Often times heroes who have been hit by Orbs while hiding in the trees will stay there, not knowing that the Orbs have provided vision of their location to your teammates. This is especially important against Monkey King. While Monkey King is using Tree Dance, any damage from Spirits will provide his location to your team and make him targetable for other spells.
Second off, Spirits will hit invisible players. This can serve as a warning sign that invisible players are approaching your position to gank. Often, expanding/contracting Orbs and attempting to mimic the pathing of an invs hero provides several Orb collisions, essentially painting a path that this invs hero is taking. This can be used to track the movement of an invs player, as well as potentially getting the kill on a hero you can’t even see.
Third off, Spirits will NOT hit illusions. Seeing Orbs fly through an enemy hero is 100% guarantee that the hero in question is fake.
How to Use Overcharge
GIVE ME SOME TIME TO RE-WRITE THIS ONE, FOLKS.
Overcharge is the most misused spell on Io. This section of the guide is a logical exploration of when and how it is viable to use Overcharge.
Overcharge drains 6% (f*ck you, 7.06c) of your current HP and MP per second in order to provide you AND your Tether target with increased Attack Speed (40-70) and Damage Reduction (5-20%).
This is a relatively straightfoward spell that is VERY EASY TO F*CK UP.
The easiest advice I can give about Overcharge is DO NOT TO LEAVE IT ON. You will kill yourself or render yourself useless without mana if you forget to de-active this spell. If you are chasing an enemy hero and not attacking, TURN OFF OVERCHARGE. You won’t gain any DPS if you’re not actually attacking. If you expect that you will be stunned or silenced, TURN OFF OVERCHARGE. Any damage that Overcharge will block from the incoming stun/silence and subsequent attacks will most likely be negated by the life-draining effect of Overcharge itself!
There are several qualities to Overcharge that are overlooked by the vast majority of Dota 2 players. Firstly, Overcharge will eventually stabilize at point where your current HP is low enough that a loss of 6% per second is LESS than your HP regen. At this point, the HP you lose from Overcharge is less than or equal to the HP regen you gain naturally per second, and when you Overcharge, you will not lose or gain net HP. This “baseline” can be raised by increasing your HP regen.
Secondly, the higher your CURRENT HP is, the more damage you will take from Overcharge per second. This is relatively straightforward – 6% of 2000 is more then 6% of 100. Because Overcharge takes a PORTION of your HP, no matter how much is available, the less you have, the less it will take, until you reach your baseline.
Because the cost of using Overcharge is so high (6%/sec of your HP/MP is no joke), an important question to ask is: When should you be overcharging? When should you not be overcharging?
Overcharge has 2 functions, one for Attacking (attack speed) and one for Defense (damage reduction). In order to answer the question of when best to Overcharge, we must compare each of these states (Attack and Defense) against the two types of Tether states, UnTethered (Solo) and Tethered.
Attack * Solo –> Good
If you’re alone, you can use Overcharge to increase your own attack speed. This can help Io get kills by increasing his DPS in conjunction with his other skills. It is dangerous, because you are paying HP and MP to increase how rapidly you take away another player’s HP, so use with care. This is also a good tactic for pushing towers and rax. Just make sure not to lower your HP too significantly in case enemy heroes are nearby, and to heal if you can.
Attack * Tethered –> DOUBLE GOOD
This is the single BEST way to use Overcharge. You are paying the same cost as in Attack * Solo, but you are getting double the net attack speed (once for you, and once for your Tether target). This greatly increases DPS output from you and your teammate and can net your team important kills and pushed towers.
Defense * Solo –> BAD. SUPER BAD. REALLY REALLY F*CKING BAD.
This is the WORST way to use Overcharge. The logic here is that you are attempting to block incoming damage onto yourself by activating Overcharge. However, often times the damage reduced by Overcharge is not worth the HP loss that Overcharge inflicts. The example below illustrates this concept.
I have built an Excel Spreadsheet that calculates the damage Overcharge deals to Io per second. Lets say Io has 1000 HP, and an HP regen of 8 HP/sec. Lets say a Lina is chasing the Io and wants to cast her Lv 2 Ultimate Laguna Blade (650 magic damage, 487.5 HP points after 25% magic resistance). Io begins Overcharging as he runs away, expecting to be hit with spells. He is able to make it for 3 seconds before Lina ultimates and hits him with Overcharge activated.
After 3 seconds, Io has Overcharged himself from 1000 HP to 856 HP. Once the Lina ultimate hits Io, Overcharge removes 20% of the 487.5, and the Lina ultimate hits for 390 HP points worth of damage. Io immediately turns off Overcharge, and sits at 466 HP.
If Io had NEVER OVERCHARGED AT ALL, the Lina ultimate would have hit for 487.5 HP points worth of damage, and Io would be sitting at 512.5 HP.
It’s clear from this example that even a brief overestimation in Overcharge can have a net negative effect on Io’s survivability. Even in this example, the time it takes for the Lina ultimate to make contact, and the time it takes for Io to turn off the Overcharge, is set to 0 seconds, when in reality it would be another additional second of reaction time before Overcharge could be turned off, dealing even more damage to Io.
Using Overcharge to block self-damage is functional IF THE TIME SPENT OVERCHARGING IS EXTREMELY SHORT (~1 second). Turning on Overcharge the moment before a Sniper Headshot hits you, and then immediately turning it off again, will block 20% of Sniper’s damage while hurting you relatively little. The problem with examples like this is that very few spells are so obvious as to be able to predict the exact moment they will hit. Overcharging for even a few seconds on either side of the incoming spell would negate the damage blocked by Overcharge in the first place.
Defense * Tethered –> Good
Overcharge can be used to block incoming damage on a Tethered teammate. This is a valid way of using Overcharge because it presumes Io is not being focused by enemy damage. Io is sacrificing his own HP/MP, but it’s done in order to ensure another hero’s HP does not drop to zero. Overcharge also comes into play as a HP-lowering spell, in order to ensure that Io’s self-healing items will have maximum effect on the Tethered party.
If you activated Overcharge for an infinite period of time, Io would not die. At some point, Io would lose so much HP that the 6% HP/sec loss Io experiences from Overcharge would be EQUAL to the amount of passive HP regen Io gains every second. This is Io’s “Overcharge Baseline”, meaning the total HP amount at which Overcharge will no longer drain HP/MP from Io.
Why should you care about this? Because, as shown previously, using Overcharge to block incoming damage on Io often has a net-negative effect; HOWEVER, the amount of negative feedback from self-damage-block-Overcharging varies according to how much HP you lose during the Overcharge. If you are familiar with your Overcharge Baseline, you can better understand and predict when it is appropriate to use Overcharge to block incoming damage on Io, because if you Overcharge close to your baseline, you lose very little HP in exchange for 20% damage reduction.
Your Overcharge “baseline” is defined by the following mathematical relationship: 1 HP regen = 16.666666 HP. If you have 8 HP/sec, your baseline is 133.33 HP, meaning that if you activate Overcharge when your HP is at 133.33, you will not gain nor lose HP. If you Overcharged very close to your baseline, lets say 150 HP, you would only lose a very small fraction per second (<1 HP). If you Overcharged at 110 HP, you would gain net HP, despite the damage from Overcharge.
Your baseline varies according to your HP regen. 8 HP/sec has a baseline of 133.3 HP. 10 HP/sec has a baseline of 166.66 HP. 20 HP/sec has a baseline of 333.33 HP. Etc etc etc.
Overcharging close to your baseline presents a loop-hole to the previously stated argument that self-damage-block-Overcharging is bad: if you are barely losing any HP/sec during the Overcharge, the 20% damage block becomes viable and useful. Lets present another example to illustrate this principle.
Io sits at 216.66 HP with 13 HP regen/sec, and therefore 216.66 is his baseline (16.66 * 13 = 216.66). In one reality, Io does not overcharge. Over 4 seconds, he gains 52 HP (13 HP/sec * 4 sec), moving to 268.66 HP. After the 4 seconds, he is hit with a spell that deals 270 damage, and dies. In the second reality, Io overcharges for 4 seconds. He does not gain or lose any HP, and is still at 216.66 at the end of the 4 seconds. He is then also hit with a 270 damage spell, but now survives, blocking 20% of the 270 (270*.8 = 216) and taking 216 damage. He survives with 0.66 HP remaining.
So, in summary:
(1) Overcharge to increase your damage output
(2) Overcharge to increase your + another’s damage output
(3) Overcharge to block damage on another hero and to ensure your healing is effective
(4) DO NOT Overcharge to block damage on yourself, UNLESS your HP is close to your baseline
How to Use Relocate
Double-tapping the Relocate button (“R” for some players, “4” for others) should activate Relocate and teleport you back to your base. If this does not work for you, you can change the “double-tap an item/spell to activate it on yourself” option in the Settings menu.
Relocate teleports Io and a Tethered target to anywhere on the map for 12 seconds. After 12 seconds, Io and anyone he is Tethered to will be Returned to their original position.
(1) Escape or Save a Teammate
Relocate can be used to escape death by Relocating back to your base. This is effective because it negates the enemy team’s pressure on you and in the process can waste valuable cooldowns and put enemy heroes out of position. Being back in the base refreshes Io’s HP and MP, allows him time to buy valuable items (especially if you think, on the Return, you will most likely be killed), and buys time for your teammates to move to the fight and engage with the enemy.
This principle is the same for when you are Tethered to another teammate. If someone is being Duel by an Legion Commander, or Dismember by a Pudge, or simply has low HP, you can Relocate them to safety. MAKE SURE to activate Tether before Relocate or else the channeling of the Relo will be interrupted. Overcharge is also a good idea, to prevent the target from dying before Relocate activates.
You will have to make a judgement call about the Return, and whether or not it is a good idea to bring back the person you saved. If 5 enemy heroes are waiting for your Return, it might be best to leave the hero you saved and accept your death. 2 dead heroes is always worse than 1.
There are several common locations for Relocate. The first is back to base, where the healing and item purchasing can occur. This is where 98% of my save/escape-based Relocates are headed.
The second Relocate location is just outside of a teamfight. If a teammate is disabled by a spell, such as Batrider Flaming Lasso, teleporting that teammate all the way back to your base for 12 seconds removes two allied heroes from the teamfight (You + Teammate), which can weaken the position of your other teammates and could potentially lose you the teamfight. Instead, you can Relocate with that hero only several hundred units away – enough to break the disable spell, but not so far that they cannot participate in the teamfight. This saves your teammate AND stops the teamfight from becoming lopsided in favor of the enemy.
The third and least common use of Relocate takes a different approach. Rather than fighting with your team and Relocating to safety (only to Return back to the fight, which could be very dangerous) some professional Io players will opt to use a Teleport Scroll back to base, and then Relocate BACK to the fight. This provides the benefit of being able to Tether another teammate to safety upon your Return, while also increasing Io’s survivability by ensuring he has 100% HP/MP. However, if the fight lasts longer than 12 seconds, Io is unable to teleport back to help further (as both Relocate and TP scroll will be on cooldown).
Relocate can be used to gank enemy heroes anywhere on the map. This is best performed when Tethering to another hero, to increase the DPS you can output in only 12 seconds.
When Io Relocates to a location, there is a “swirl” on the ground at the target location that is visible to enemy players. As a result, it is important to hide this swirl. The best way to do this is to Relocate into some trees that are near your ganking target. The trees will break when Relocate activates, so you do not have to worry about being stuck in the trees, and the enemy hero will have no visual clue that you are coming to gank.
A riskier option is to Relocate DIRECTLY ON TOP of the enemy hero, so that his character model covers the swirl. If the hero moves, however, he will most likely see the swirl and register that an Io + Teammate is incoming, so this is best performed on stationary heroes.
There is an auditory cue that your enemy can hear (the “charging up” noise that you hear when you Relocate) regardless of his ability to see the “swirl”. Keen players will hear you coming and react accordingly, so be careful!
(3) Dive/Killing Runners
Relocate can be used to catch low-HP enemy heroes that are running back through a lane towards their base. This will require some timing on the part of the Io, but the range of Spirits allows Io to deal high damage to far-away heroes, while Relocate ensures you will be Returned to your original position, no matter how deep you have to dive.
This can be used by advanced players to cut off opponents in their own base before they reach their fountain. Make sure you can survive the full 12 seconds!
(4) Pushing (aka Rat Dota)
Relocate can be used to push towers and rax, as long as there is no backdoor protection. The 12 second Return ensures that no matter how dangerous or risky the positioning is, Io + Tether buddy will always be returned to safety. Bringing a Tethered hero is required for maximum DPS, and choosing the top-damage hero on your team ( Tiny with Aghs is a great choice, or any hero with Desolator) will ensure for fast pushing.
Backdoor tower/rax regeneration is still an issue, but if the tower/rax has low enough HP, you should be able to finish it off before the Relocate is over, even if Backdoor Protection is active.
This Relocating tactic combos incredibly well with both Lv25 talents, and forces the enemy players to remain close to base to defend against potential Relocates. This is a valuable method for controlling enemy movement in the endgame.
(5) Defending Towers
Io can use Relocate, if needed, to engage creeps that are hitting towers. While it is not the best use of the spell, the 12 seconds allows Io to eliminate one, if not two creep waves that are pressuring a tower that no one is defending.
(6) Changing Tether Targets Mid-Relocate
When Io Tethers to any target, the Tether lasts for 12 seconds, and has a cooldown of 12 seconds. HOWEVER – when Io Relocates, this refreshes his Tether, BUT NOT THE COOLDOWN. This means you can potentially have a 24-second-long Tether, by Tethering for almost 12 seconds and then activating Relocate before Tether expires.
It also means that if you Tether a target for several seconds, and then Relocate to a new area, you can Break your Tether and re-Tether a new target to bring with you on your Return. Because the cooldown of Tether is not refreshed upon Relocate use, this allows you to bring Hero A into a teamfight, then re-Tether to Hero B and bring him to safety.
(7) Return can be CANCELLED?!
The Return portion of Relocate is one of the strongest spells in the game. It cannot be overpowered by any stun, root, disable, or item (such as Eul’s Scepter of Divinity). There are, however, some ways in which Io will NOT be Returned to his original location.
The first is through Pudge Meat Hook. If Pudge hooks Io, and Io is being dragged towards Pudge as the Return activates, Io will Return to his original position before being teleported back to Pudge. Something about the way Hook works with heroes and positioning means that Io will not be Returned. This can be used POSITIVELY, such as a teammate Pudge saving you from a bad Return, or NEGATIVELY, by a enemy Pudge preventing you from escaping.
The second way to cancel Return is through other “returning” spells. [Kunkka] [X Marks the Spot] is a classic example, whereby Kunkka can X the Io, wait for him to Return, and then activate the X spell to bring Io back. [Keeper of the Light] [Recall] is another example of this, where KotL can start the Recall spell before Io has Returned, and time it so that the Recall spell will activate very soon after Io Returns. A well-timed [Underlord] [Dark Rift] can accomplish the same thing.
The third way to cancel Return is via a Teleport Scroll, and is without a doubt the MOST DIFFICULT Return cancel to perform. It operates on the idea that if the Teleport channeling spell completes itself at the
exact moment that Io Returns, the Teleport will override the Return, and the Io will move to the Teleport location and not the Return location.
My best advice to accomplish a TP scroll Return-Cancel is to activate the scroll just before the countdown timer for Return hits “3”. There are several microseconds of time between clicking the intended location of the Teleport Scroll and 3-second channeling spell actually beginning, and this must be factored in when trying to execute this move. The window for activating the TP scroll successfully is INSANELY small (several frames, I would imagine), and you will fail more than 9 times out of 10. Activate the TP too early, and the Relocate will cancel the channeling spell. Active the TP too late, and Io will successfully TP… and then Return. Practice makes perfect.
(8) Relocate and Glimmer Cape – Two Best Friends
Glimmer Cape is your best friend, especially when it comes to Relocate. While Glimmer Cape may help you activate the Relocate without being stunned (although you will break Glimmer’s invisibility when you start the Relocate spell), it is mainly used on the Return portion, where one or several enemies may be waiting to kill you.
Glimmer Cape provides 5 seconds of invisibility after a 0.6 second pause. Glimmer can be activated 1 second before you Return, and will render you invisible for when you Return to your original position. This will buy you valuable seconds to move away from the Return location and potentially Tether away to safety. Enemy heroes will be staring at the “swirl” that is left by your Relocate, and will simply see the swirl disappear without any presence of Io. This confusion also plays to your advantage in moving away from the area.
(9) Double Relocate
If, by some god-given miracle, you have a Refresher Orb (or Refresher Item dropped by Roshan), you can technically Relocate somewhere with a 12 second Return cooldown, and then during that cooldown Relocate AGAIN somewhere else, with another 12 second cooldown. What the heck happens then?
If you Relocate twice, your primary Return point is all that matters. If you Relocate from Spot A to B, and then Relocate again from B to C, you will Return from C to A. You will also return in 12 seconds from the primary Relocate – you cannot extend the 12-second Relocate window and it cannot stack, either.
This does have some expensive uses. For instance, you can Relocate from your base to your carry, Relocate again with the carry to a teamfight, and then Return to base with an injured teammate. Remember that the activation of Relocate (as well as the Refreshing trigger you’re using to cause this effect) will reset the cooldown of your Tether, and that also means you can bring different allies to Stages A, B, or C with ease.
In this section I defend my logic behind my Talent choices.
Lv 10 –> +45 Damage or +20% XP
Io’s Lv15, Lv20, and Lv25 talents are extremely powerful. Getting to them faster with the Lv10 +20 XP talent is beneficial to maintaining your survivability, overpowering the enemy and remaining relevant despite your support position.
+45 Damage is viable when you are Mid Lane, Core Io, or simply crushingly ahead of your opponents by Lv10. If you can end the game quickly and need to maintain your snowball, go for the +45 Damage boost at Lv10. Otherwise, +20% XP is what you need.
Lv 15 –> +75 Spirits Damage or Tether/Aghanim’s
(R.I.P. +10 Mana Regen. You will be missed.)
Many people, when 7.07 was first released, saw the “Tether Gives Ally Aghs” talent and lost their ******* minds. They thought this was either 1) the most broken thing or 2) the greatest thing to ever happen to Dota. I disagree on both counts.
Tether/Aghs is a very situational talent – one I would suggest getting if you are playing with friends and can coordinate/communicate with them very effectively. Many allies on your team have ultimates that require you to be Tethered to them BEFORE they activate said ultimate in order for it to be Aghs buffed. Other heroes don’t have Aghs buffs at all. OTHER OTHER heroes….are bad players, who are currently 1-7-3 in your game and you don’t trust them to use their ultimates effectively. This often leaves 1 or 2 heroes out of the potential 4 that could actually use your Tether/Aghs effectively.
Because of the hype surrounding the Tether/Aghs talent, the +75 Spirits talent has sort of fallen under the radar – which is insane, because it’s incredibly, incredibly powerful. Spirits hit for 80 damage per orb, so +75 is ALMOST DOUBLE SPIRITS DAMAGE. This means that Spirits moves from 400 damage per cast at lv 7 to 775 damage per cast at Lv15 – that’s enormous! Not only that, but this bigger damage output means that percentage-based increases to magic damage (such as Veil of Discord, Kaya, bonuses gained through Intelligence) have even more impact. Most importantly, +75 Spirits Damage requires no coordination with your teammates. It is always active, always working, where as Tether/Aghs is INCREDIBLY situational even within a game where you have good targets.
I personally pick +75 Spirits Damage >95% of the time.
Lv 20 –> +150 Gold/min or “+15 HP Regen”
150 GPM allows you to purchase heavy endgame items than can situationally shut down opponents. Need to finish Heart of Tarrasque to heal your carry? Need to get Scythe of Vyse to sheep the enemy Tinker? Need to get a fast Desolator so you can start Relocating into the enemy towers? This talent is what you need.
It’s important to remember that the faster you hit Lv20 and get the GPM talent, the more gold it generates for you in a given game. That being said, this combos extremely well with the Lv10 +20% XP talent which will level you up (and make you richer) that much faster.
+15 HP Regen is not to be forgotten about. The +15 HP Regen is multiplied in power by your Str stat, meaning this talent actually gives Io almost +25 HP/sec. This is powerful, but it is not as versatile as a gold boost (which can be spent on a variety of items/abilities) that could potentially buy a HoT that would give you +200 HP/sec. Situationally this talent can work, but I consistently pick Gold over HP.
Lv 25 –> -60s Relocate or Attack Tethered Ally’s Target
Thank you so much to the Dotafire community for putting this guide as the #1 spot on the “Top Dota 2 Guides (Last 30 Days)” charts from 2-19-17 to 3-20-17, as well as for winning the Dotafire Guide Contest in the Strength Hero Category on 10-5-17.
I hope that by reading through this guide (or just the portions you were interested in) that you have gained a deeper understanding of Io strategy, and that I have effectively defended my reasoning behind the decisions I made.
I plan to use this guide as my own personal record of successful Io ideas, and I will be updating this guide as I find new combos and item combinations that are more effective than the last. So feel free to check back in a few months and see what I’ve come up with.
A big thank you to everyone who has said nice things about this guide, subscribed to my channel, or sent positive feedback. Hopefully you guys can be pulling moves like this soon –
And an extra special thank you to everyone who gave me advice or guidance about Io – I couldn’t have done it without you.