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Io icon.png
Strength attribute symbol.png
Agility attribute symbol.png
Intelligence attribute symbol.png
17 + 3
14 + 1.6
23 + 1.7
Level 0 1 15 25 30
Health 200 540 1380 2220 2560
+0.25 +1.95 +6.15 +10.35 +12.05
Mana 75 351 627 975 1107
+0 +1.15 +2.34 +3.79 +4.32
Armor 1 3.33 7.07 11.73 13.4
Damage Block -
Magic Resistance 25%
Status Resistance 0%
Damage 28‒34 45‒51 87‒93 129‒135 146‒152
Attack Rate 0.59/s 0.67/s 0.8/s 0.97/s 1.03/s
Attack Range Ranged 500 (800)
Attack Speed ▶️ 100 (1.7s BAT)
Attack Animation 0.3+0.4
Projectile Speed 1200
Movement Speed ▶️ 320
Turn Rate Takes 0.15s to turn 180°. 0.7
Collision Size 24
Vision Range (G) 1800 • 800
Legs 0
Gib Type Ethereal
Ability Upgrades
Upgradable by Aghanim's Scepter.
Upgradable by Aghanim's Shard.

Links to its allies to buff them.
The phenomenon that is Io manifests on the physical plane as a wisp of light, its purpose beyond mortal understanding. It flits to and fro the battlefield, searching for an ally to Tether to. Those blessed with Io's bond feel their feet lighten as the Wisp channels its own regenerative powers into their body. Should its host falter, Io begins to Overcharge, augmenting that ally's speed while strengthening his resolve. As a force unbound by the laws of corporeal space, Io is able to temporarily Relocate itself and an ally to any point in the world, often saving a companion from certain death.
Roles: Support Support Escape Escape Nuker Nuker
Complexity: ★★★


Io minimap icon.pngIo, the Wisp
▶️ *Beep Boop*
Io is everywhere, and in all things. Denounced by enemies as the great unmaker, worshiped by scholars as the twinkling of a divine eye, this strange Wisp of life-force occupies all planes at once, the merest fraction of its being crossing into physical existence at any one moment.

Like the great twin riders Dark and Light, and yet another ancient traveler whose true history is lost to the ages, Io the Wisp is a Fundamental of the universe, a force older than time, a wanderer from realms far beyond mortal understanding. Io is nothing less than the sum of all attractive and repulsive forces within the material field, a sentient manifestation of the charge that bind existence together. It is only in the controlled warping of these electrical waylines that Io's presence can be experienced on the physical plane. A benevolent, cooperative force, Io bonds its strange magnetism to others so that the power of allies might be enhanced. Its motives inscrutable, its strength unimaginable, Io moves through the physical plane, the perfect expression of the mysteries of the universe.
Itself (Responses)


Tether icon.png
Target Unit
(Upgradable by Aghanim's Shard. Passive)
Allies / Self
Tethers Io to an allied unit, granting bonus movement speed to both. When Io restores health or mana, tethered units target gains a larger portion of that amount. The tether breaks when the allied unit moves too far away, or Io cancels the tether.
Cast Animation: 0+0
Cast Range: 1600
Tether Break Distance: 1000
Tether Pull Distance: 700
Tether Break Distance During Pull: 2150
Heal/Restore Transfer: 75%/90%/105%/120%
Target Move Speed Bonus: 6%/8%/10%/12% (Talent 12%/14%/16%/18%)
Enemy Move Speed Slow: 15%/25%/35%/45%
Enemy Attack Speed Slow: 15/25/35/45
Slow Duration: 0.2
Talent Attack Damage Bonus: 15
Talent Health Bonus: 400
With Aghanim's Shard Passive Spell Lifesteal Bonus: 10%
Cooldown: 12
Mana: 40
Upgradable by Aghanim's Shard.
Aghanim's Shard Upgrade:
Io gains Spell Lifesteal and can now share Spell Lifesteal with its tethered target.
Not disabled by Break.
Break Notes:
Upgradable by Aghanim's Shard.
Does not disable the passive spell lifesteal.
Modifiers [?]
The benevolent touch of Io brings strength from between the planes.


  • Tethering a unit that is 700 units or further away causes Io to latch on and pull itself to the target.
    • Pulls Io at a speed of 1000, until coming within 300 range of the target.
    • Can pull Io over impassable terrain and through trees. Destroys trees within 150 radius around Io once the pull ends.
    • If Io breaks the tether while getting pulled to the tethered target, the pull immediately stops.
    • The pull gets interrupted when Io gets stunned, hexed, hidden, feared, hypnotized, or rooted during the pull.
    • Forced Movement cancels the pull as well, but only after the movement ends, and not upon getting applied.
    • Taunts, leashes, and silences do not interrupt the pulling.
    • If the distance between Io and the target gets greater than 2150 during the pull, the pull ends and the Tether breaks.
  • If the distance between Io and the target gets greater than 1000, the Tether breaks.
    • When the distance between Io and the tethered target gets greater than 700, the link's visual appearance changes.
  • Tether has no set duration. It breaks only when exceeding the break distances, when Io or the target dies, when affected by an allied Upgradable by Aghanim's Shard. Dismember, or when using the Break Tether sub-ability.
  • The movement speed bonus is only applied to the tethered ally, while Io copies the target ally's movement speed.
    • Sets Io's base movement speed equal to the base speed of the target, plus any speed bonuses they have, flat and percentage.
    • Since it sets Io's base movement speed, percentage-based movement speed bonuses and slows are based on this value during Tether.
    • Fully overrides any flat movement speed bonuses and reductions on Io, from items and abilities alike.
    • If the target is slowed, the slow is not copied by Io. Tether copies the target's movement speed as if they are not slowed.
    • Does not copy the target's movement speed while Io is hasted.
    • While tethered, Io cannot bypass the maximum movement speed limit, even if the tethered ally does.
      • Prevents other abilities from unlocking the movement speed limit as well (e.g. Force Boots icon.png Force Boots, Thirst).
  • The tethered unit benefits from Overcharge, Relocate, and from Io regenerating or replenishing health and mana.
    • Tethered units still benefit from all those effects even when turning invulnerable or hidden.
    • The heal and mana restore transfer happen regardless of how much Io actually healed/restored.
    • The health/mana transfer percent is applied after all reductions/amplifications on Io.
  • If Io or the tethered unit is invisible, enemies can only see a fake link leading to the invisible unit's last known location. If the tethered unit is visible to the enemy, enemies can still see the unit is tethered.
  • The movement speed slow gets applied to every enemy that comes within approximately 55 range of the tether link on each server tick.
  • The tethered attack damage bonus Talent talent grants its bonus to the target and to the caster.
    • Learning the talent immediately updates the Tether buff on the target and the caster.
    • Grants regular flat bonus attack damage.
  • The tethered health bonus Talent talent grants its bonus to the target and to the caster.
    • Learning the talent immediately updates the Tether buff on the target, but not the buff on the caster.
    • The health talent increases maximum health capacity, and keeps the current health percentage.
  • The movement speed bonus increasing Talent talent does not update the Tether instance.
  • The attack tethered ally target Talent talent causes Io performs instant attacks on every enemy the tethered ally attacks.
    • These instant attacks can proc any attack modifiers and on-hit effects normally. They do not have True Strike.
    • The attacks are performed as soon as the ally launches their attack (including instant attacks from the ally). It does not matter whether the attack actually hits or not.
    • If Io is stunned or disarmed, no instant attack is performed.
    • Does not perform attacks when the tethered target also has this talent (i.e. an illusion of Io).
  • With Aghanim's Shard icon.png Aghanim's Shard, Tether passively grants Io spell lifesteal, and grants Io's total spell lifesteal to the tethered target as well.
    • Stacks additively with other sources of spell lifesteal.
    • Heals for 2% from non-hero units. Treats creep-heroes as creeps and does not heal off of illusions.
    • The shared spell lifesteal is still sourced to Io, not to the tethered ally.

Break Tether
Does not proc any on-cast effects when cast. QT
Break Tether icon.png
No Target
Break the link to the tethered unit.
Cast Animation: 0+0
Initial Cooldown: 0.25
Cooldown: 1
Mana: 0
Sub-ability of Tether.


  • Replaces Tether until the sub-ability is used or the tether is broken.
  • Break Tether goes on a 0.25-second cooldown when Tether is cast, this is to prevent accidental double-casts and prematurely ending the ability.

Spirits icon.png
No Target
(Upgradable by Aghanim's Scepter. Passive)
Summon five particle spirits that dance in a circle around Io. If a particle collides with an enemy hero, it explodes, damaging all enemy units in an area around it. Creeps take minor damage from touching a particle spirit, but do not cause them to explode. When its duration ends, any remaining Spirits explode.
Cast Animation: 0+0
Non-Hero Collision Radius: 150
Hero Collision Radius: 110
Explosion Radius: 360
Number of Spirits: 5
Collision Damage: 10/15/20/25
Explosion Damage: 30/50/70/90 (Talent 75/95/115/135)
Duration: 19 (With Aghanim's Scepter Infinite)
With Aghanim's Scepter Explosion Move Speed Slow: 15%
With Aghanim's Scepter Slow Duration: 0.3
Cooldown: 26/24/22/20
Mana: 120/130/140/150
Upgradable by Aghanim's Scepter.
Aghanim's Scepter Upgrade:
Spirits now passively spawn around Io constantly every second up to the max. Spirits colliding with enemy Heroes slows them briefly.
Not disabled by Break.
Break Notes:
Upgradable by Aghanim's Scepter.
Does not disable the passive spirits spawning.
Modifiers [?]
Io twists the particles of the universe with his unimaginable capabilities.


  • Summons a spirit in 1-second intervals, starting immediately upon cast, taking 5 seconds to summon all 5 spirits.
    • The first spirit is always spawned to the north of Io, with the next spirit spawning behind the previous spirit.
    • The spirits expand automatically to their maximum distance upon cast.
    • The spirits always rotate clockwise and are locked to Io's location, following it wherever it goes.
    • Moving the spirits in or out does not break their formation. They always rotate in a circle and keep an equal distance from each other.
  • The spirits complete a revolution every 2.7 seconds regardless of distance from Io.
    • Their angular velocity is constant, meaning their speed increases the further away they are from the caster.
    • This means the first created spirit can rotate at most 7 times around Io.
  • When a non-hero unit, illusion, or a creep-hero comes within 150 radius of the spirits, it takes the collision damage.
    • Heroes and the Lone Druid Spirit Bear icon.png Spirit Bear do not take this collision damage.
  • When a hero, or a creep-hero comes within 110 radius, the spirit explodes, dealing the explosion damage and slowing enemies within a 360 radius.
    • The explosion damage and slow affect all enemies within the area, not only heroes.
    • The explosions first apply the damage, then the slow.
  • Remaining spirits explode simultaneously at the end of the duration or if recast, dealing the explosion damage around them.
  • Spirits provide 150 radius flying vision for 3 seconds at the location where they collided with a hero.
    • They do not provide vision when exploding caused by expiring or recasting.
  • The spirits are invisible to the enemy if Io is invisible.
  • Can deal up to 150/250/350/450 (Talent 375/475/575/675) damage to a single unit when all spirits explode on a target (before reductions).
  • With Aghanim's Scepter icon.png Aghanim's Scepter, Spirits turns into a passive ability, constantly spawning spirits around Io.
    • The Spirits In and Spirits Out sub-abilities become permanently available as well.
    • When acquiring Aghanim's Scepter while a cast is already active, the spirits from that cast disappear without exploding.
    • When losing Aghanim's Scepter, the spirits from it disappear immediately, without exploding.

Overcharge icon.png
No Target
Self / Allies
Io gains bonus attack speed, spell amplification, and HP Regen based on max health. If Io is tethered to an ally, that unit also gains the bonuses.
Cast Animation: 0+0
Attack Speed Bonus: 25/55/85/115
Max Health as Health Regen Bonus: 0.5%/0.6%/0.7%/0.8% (Talent 0.7%/0.8%/0.9%/1%)
Spell Damage Amplification: 8%/10%/12%/14% (With Aghanim's Shard 18%/20%/22%/24%)
Duration: 8
Cooldown: 25/22/19/16
Mana: 40/60/80/100
Upgradable by Aghanim's Shard.
Aghanim's Shard Upgrade:
Increases Overcharge Spell Amplification.
Modifiers [?]
Drawing on the energy of matter from all worlds, Io begins the unravelling of time.


  • Io does not need to be already tethered to the target transfer Overcharge. Tethering afterward transfers it as well.
    • The Overcharge on allies does not show a duration, and always appears like a permanent buff.
  • Can regenerate up to 4%/4.8%/5.6%/6.4% of Io's max health over the duration.
    • Can restore up to 4%/4.8%/5.6%/6.4% of the target's max health, plus 3%/4.32%/5.88%/7.68% of Io's max health on the tethered ally.
    • The max health regeneration increasing Talent talent does not update on the current Tether instance.
    • The Talent talent further increases the health restore up to 5.6%/6.4%/7.2%/8% of the target's max health, plus 4.2%/5.76%/7.56%/9.6% of Io's max health on the tethered ally.

Spirits In
Does not proc any on-cast effects when cast. DD
Spirits Movement icon.png
Calls the spirits closer to you. Can be toggled on and off.
Cast Animation: 0+0
Min Distance: 200
Cooldown: 0
Mana: 0
Sub-ability of Spirits.


  • This ability is hidden if Io does not have the spirits buff.
  • Does not interrupt Io's channeling abilities upon cast.
  • Moves the spirits towards Io at a speed of 250. It takes 1.8 seconds from moving the spirits from maximum to minimum distance.

Spirits Out
Does not proc any on-cast effects when cast. FE
Spirits Out icon.png
Sends the spirits farther away from you. Can be toggled on and off.
Cast Animation: 0+0
Max Distance: 650
Cooldown: 0
Mana: 0
Sub-ability of Spirits.


  • This ability is hidden if Io does not have the spirits buff.
  • Does not interrupt Io's channeling abilities upon cast.
  • Moves the spirits away from Io at a speed of 250. It takes 1.8 seconds from moving the spirits from minimum to maximum distance.

Relocate icon.png
Self / Allied Heroes
Teleports Io and any tethered ally to any location. After the spell expires Io and any tethered ally will return to their original location. Double-click to teleport to your team's base fountain.
Cast Animation: 0+0.53
Cast Range: Global
Effect Delay: 3.5/3.25/3
Duration: 12
Cooldown: 100/90/80 (Talent 75/65/55)
Mana: 175
Cannot be cast while rooted or leashed.
Root Notes:
Can be cast while rooted.
Does not teleport Io or the tethered ally while Io is still rooted as the delay finishes.
Modifiers [?]
Io is the embodiment of the mystery of the universe.


  • If Io is rooted, stunned, slept, cycloned, or hexed during the effect delay, Relocate gets cancelled.
    • If Io is silenced as the delay finishes, the teleport does not happen.
    • Disabling the tethered ally of Io does not prevent the ally from getting teleported if Io successfully does so.
    • The returning teleportation cannot be prevented.
  • Enemies get a Ping on their minimap during the teleport delay, showing them where Relocate was targeted.
    • Creates a visual effect at the targeted point during the teleport delay, which is visible to everyone.
    • Creates a visual effect at Io's position before the teleport happens, which also is visible to everyone.
  • Relocate interrupts channeling abilities and every current order of Io and the tethered ally both on initial teleport, and when teleporting back.
  • Disjoints projectiles for Io upon teleporting to the targeted point, but does not disjoint upon teleporting back.
    • Does not disjoint projectiles for the teleported ally, neither upon teleporting to the target point, nor upon teleporting back.
  • Io may Break Tether at any time to prevent bringing an ally back.
  • Teleports invulnerable and hidden targets.
  • Destroys trees within 150 radius around Io upon both teleports.


Hero Talents
Attack Tethered Ally's Target25+400 Health to Tethered Units
-25s Relocate Cooldown20+0.2% Overcharge Max HP Regen Bonus
+45 Spirits Hero Damage15+6% Tether Movement Speed
+15 Attack Damage to Tethered Units10+4 Health Regen

Recent Changes[]

Main Article: Io/Changelogs
  • Rescaled Overcharge attack speed bonus from 50/70/90/110 to 25/55/85/115.
  • Rescaled Tether heal/restore transfer from 70%/90%/110%/130% to 75%/90%/105%/120%.
  • Overcharge
    • Reduced spell damage amplification from 10%/12%/14%/16% to 8%/10%/12%/14%.
    • Increased cooldown from 22/20/18/16 to 25/22/19/16.
  • Aghanim's Scepter icon.png Aghanim's Scepter upgrade:
    • Now also causes Spirits to apply a 15% movement speed slow for 0.3 seconds when hitting an enemy hero.
  • Reworked Aghanim's Shard icon.png Aghanim's Shard upgrade:
    • Old: Increases Tether movement speed bonus by 8% and causes it to deal 150 damage and stun enemies for 1.75 seconds upon them coming within its slow range. Can affect the same unit once every 7 seconds.
    • New: Increases Overcharge spell damage amplification by 10%. Makes Tether passively grant Io 10% spell lifesteal and causes it to share Io's current spell lifesteal with the tethered target.
  • Talent Talents:
Level 10 left talent changed: +30 attack damage ➜ +15 attack damage to Tethered units. [?]
Level 15 left talent changed: +15% spell lifesteal ➜ +45 Spirits explosion damage.
Level 15 right talent changed: +300 Spirits max distance ➜ +6% Tether movement speed bonus.
Level 20 right talent changed: +60 Spirits explosion damage ➜ +0.2% Overcharge max health as health regeneration bonus.
Level 25 right talent changed: +900 health ➜ +400 health to Tethered units. [?]
Level 10 right talent: +5 health regeneration reduced to +4.
Level 20 left talent: -30s Relocate cooldown reduced to -25s.

Recommended Items[]

Starting items:

  • Tango icon.png Tango provides health regeneration to Io and a lane partner, thanks to Tether.
  • Healing Salve icon.png Healing Salve keeps Io and ally up in health during the early game.
  • Clarity icon.png Clarity sustains Io and ally with mana to use abilities.
  • Enchanted Mango icon.png Enchanted Mango gives some health regeneration, as well as mana restoration.
  • Gauntlets of Strength icon.png Gauntlets of Strength increases strength so Io can hit harder and has more health. It also builds into Soul Ring.

Early game:

  • Bottle (Full) icon.png Bottle, available at the Secret Shop, restores both ally's health and mana with Tether.
  • Urn of Shadows icon.png Urn of Shadows heals Io while Tether passes that healing to an allied target.
  • Magic Stick icon.png Magic Stick instantly restores mana and health to both Io and a tethered ally.
  • Soul Ring icon.png Soul Ring grants strength and health regeneration. More importantly, Io can pass the created mana to the tethered ally so both parties can use their respective abilities. Consider items like Tranquil Boots or Helm of the Dominator that boost health regeneration to sustain the health cost of Soul Ring.

Mid game:

  • Magic Wand icon.png Magic Wand gives attributes and a bit more amount of heal compared to Magic Stick.
  • Spirit Vessel icon.png Spirit Vessel, upgraded from Urn of Shadows icon.png Urn of Shadows, increases regeneration and healing for Io to keep allies healthy, while providing bonus health and movement speed to boost Io's survivability.
  • Arcane Boots icon.png Arcane Boots restore a large amount of mana to Io and allies with Tether.
  • Mekansm icon.png Mekansm heals Io's tethered partner for much more than the standard 275. It also provides a health regeneration aura to boost survivability.
  • Helm of the Dominator icon.png Helm of the Dominator provides extra health regeneration for tethered allies, and has an attack speed aura that stacks with Overcharge. It also allows Io to dominate a creep to take advantage of its auras and abilities, as well as boosting the movement speed of both parties thanks to Tether, giving Io an option of skipping buying boots.

Late game:

  • Guardian Greaves icon.png Guardian Greaves, built from Mekansm and Arcane Boots to save an item slot, restore huge amount of health and mana to Io and its team, especially with Tether.
  • Glimmer Cape icon.png Glimmer Cape allows Io or allied target to escape from enemies with invisibility and magic resistance.
  • Ghost Scepter icon.png Ghost Scepter shields Io from physical attacks, so it stays alive longer to help allies.
  • Heart of Tarrasque icon.png Heart of Tarrasque gives a huge amount of health and health regeneration, increasing the tethered allies health regeneration and survivality.
  • Mjollnir icon.png Mjollnir provides huge damage output, which allows taking down tethered ally's targets (with the appropriate talent taken) rapidly.

Situational items:

  • Tome of Knowledge icon.png Tome of Knowledge grants experience to help Io reach its talents.
  • Tranquil Boots (Active) icon.png Tranquil Boots heals Io and tethered allies more if they do not need the mana from Arcance Boots.
  • Drum of Endurance icon.png Drum of Endurance gives cost efficient attribute bonuses and further boosts Io's and its partner's attack and movement speed.
  • Pipe of Insight icon.png Pipe of Insight grants aura of health regeneration and magic resistance, a great item to absorb magical damage.
  • Vladmir's Offering icon.png Vladmir's Offering has useful aura with many perks, including bonus attack damage and lifesteal, enabling allied physical attackers.
  • Solar Crest icon.png Solar Crest further buffs allied targets with attack speed, movement speed, and armor. Moreover, Io can use it on the enemies to slow and removes their armor.
  • Force Staff icon.png Force Staff provides useful ability to position different heroes, including Io.
  • Holy Locket icon.png Holy Locket enhances Io's healing power, as well as strengthening its defense with bonus health and magic resistance.
  • Heaven's Halberd icon.png Heaven's Halberd gives strength, evasion, status resistance, and the ability to disarm an enemy carry.
  • Scythe of Vyse icon.png Scythe of Vyse provides a valuable disable, some useful attribute bonuses, as well as mana regeneration which can pass on to tethered ally.
  • Desolator icon.png Desolator adds damage and applies armor reduction on enemies; works better in the late game after taking talent that lets Io attack tethered ally's target.






  • Io is the name of a priestess of Hera in Greek Mythology. She was seduced by Zeus and subsequently incurred Hera's wrath.
    • Io is also the name of one of four Galilean moons of Jupiter, which was named after the same character in Greek Mythology.
  • Io's fun names in DotA were Weird Ball and Santelmo. Santelmo may refer to St. Elmo's Fire, a weather phenomenon that creates sparks of bright energy similar to that of lightning, mostly occurring from sharply pointed structures. Santelmo may also refer to the Philippine's folklore creature which is a head of fire, or a ball of fire which Io resembles.
  • Enigma minimap icon.png Enigma, Chaos Knight minimap icon.png Chaos Knight, Keeper of the Light minimap icon.png Keeper of the Light, and Io minimap icon.png Io together represent the four fundamental forces of the universe with Io representing the electromagnetic force, as alluded to in its lore as the attractive and repulsive force, the charge that binds existence together, its powers over magnetism, as well as its abilities which requires Io to pull itself towards allies.
  • Io's facing direction is marked by an arc-like effect.
  • Io has several "tentacles" that randomly palpate any visible unit within 256 range of it, enemies and allies alike, randomly switching between units every few seconds. This is purely for aesthetic purposes. A hidden modifier modifier_wisp_tentacles is responsible for this effect.