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Strength attribute symbol
Agility attribute symbol
Intelligence attribute symbol
17 + 2.7
14 + 1.6
23 + 1.7
Level 0 1 15 25 30
Health 20 394 1208 2066 2418
+0.25 +1.95 +5.73 +9.63 +11.18
Mana 80 356 632 980 1112
+0 +1.15 +2.34 +3.79 +4.32
Armor 1 3.33 7.07 11.73 13.4
Magic Resist 25% 27.3% 29.68% 32.58% 33.63%
Damage Block -






Attack Rate 0.59/s 0.67/s 0.8/s 0.97/s 1.03/s
Attack Range Ranged 500 (750)
Attack Speed ▶️ 100 (1.7s BAT)
Attack Animation 0.3 + 0.4
Projectile Speed 1200
Move Speed ▶️ 320 (Nighttime 350)
Turn Rate Takes 0.224s to turn 180°. 0.7
Collision Size 27
Bound Radius 24
Vision Range (G) 1800 (Nighttime 800)
Gib Type Ethereal
Internal npc_dota_hero_wisp
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. Accompanied by complementary Spirits that roam around the wisp at its will, 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.
Spirits In
Spirits Out
Roles: Support Support Escape Escape Nuker Nuker
Complexity: Hero ComplexityHero ComplexityHero Complexity
Adjectives: Blue, Flying
Legs ( 0 )


Io minimap iconIo, 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
Target Unit
(Upgradable by Aghanim's Shard. Passive)
Self / Allies / Enemies
Tethers Io to an allied unit, granting bonus movement speed to both. When Io restores health or mana, the tethered unit gains a portion of that amount. The tether breaks when the allied unit moves too far away, or Io cancels the tether. Tether briefly slows enemies touching it.
Passive Component
With Aghanim's Shard Spell Lifesteal Bonus: 10%
Cast Range: Affected by Cast Range bonuses. 1600
Tether Break Distance: Affected by AoE Radius bonuses. 1000
Tether Pull Distance: 700
Tether Break Distance During Pull: 2150
Target Heal Multiplier: 0.6/0.8/1/1.2
Target Mana Restore Multiplier: 0.6/0.8/1/1.2
Target Move Speed Bonus: 6%/8%/10%/12% (Talent 12%/14%/16%/18%)
Enemy Move Speed Slow: 15%/25%/35%/45% (Talent 30%/40%/50%/60%)
Enemy Attack Speed Slow: 15/25/35/45 (Talent 30/40/50/60)
Slow Duration: 0.2
Talent Attack Damage Bonus: 15
Talent Health Bonus: 400
Cooldown symbol
Mana symbol
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 350 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 sources cancel 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.
    • The link changes color at 700 distance and jiggles at 800 distance.
  • 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 icon Dismember, or when using the Break Tether icon Break Tether sub-ability.
  • The movement speed bonus is first applied to the tethered ally, then it sets Io's base movement speed equal to the target's current movement speed.
    • If the target has its movement speed slowed, Tether copies the target's movement speed as if they are not slowed.
    • However, it does not copy the target's movement speed while Io is hasted.
    • Percentage-based movement speed changes on Io are now based on this set value during Tether.
    • Fully overrides any flat movement speed sources on Io.
    • While tethered, Io is prevented from and cannot bypass the maximum movement speed limit, even if the tethered ally does (e.g. Thirst icon Thirst).
  • The tethered unit benefits from Overcharge icon Overcharge, Relocate icon Relocate, and from Io regenerating or replenishing health and mana.
    • Io's health regeneration, healing, lifesteal and spell lifesteal are transferred to the ally as healing.
    • Io's mana regeneration and mana restore are transferred to the ally as mana restore.
    • Tethered units still benefit from the aforementioned effects even when turning invulnerable or hidden.
    • The heal and mana restore transfer happens regardless of how much Io actually healed or restored, and is applied after all restoration manipulation sources on Io.
    • Io's health and mana regeneration values are checked and transferred to the target in 0.1-second intervals, while the heal and mana restore values are checked and transferred on each server tick.
  • 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.
  • Tether now passively grants Io spell lifesteal and the 10% spell lifesteal is also shared with the Tethered target.
    • Other spell lifesteal sources on Io are not shared.
    • Stacks additively with other sources of spell lifesteal.
    • Heals for 2% from creeps. 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.
    Most of Tether's Talent talents affects both the target and Io.
    • The attack damage bonus Talent talent immediately updates the Tether buff both on the target and Io.
    • The ally movement speed bonus increasing Talent talent immediately updates the Tether buff on the target and Io.
    • The health bonus Talent talent immediately updates the Tether buff on the target and Io.
      • The health talent increases max health capacity and keeps the current health percentage.
      • Treats illusions and creep-heroes as creeps.
    • However, the enemy movement speed and attack speed slow Talent talent does not update the current 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.
    • For Melee melee units, if the enemy target is 350 range farther than the attacker's range, the attack will always miss.
    • 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).
  • Immediately breaks upon losing ability.
  • Immediately breaks upon losing ability and while Morph icon Morphing back to original form.

Break Tether
Does not proc any on-cast effects when cast. QT
Break Tether icon
No Target
Break the link to the tethered unit.
Initial Cooldown: 0.25
Cooldown symbol
Mana symbol

  • Replaces Tether icon 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
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.
Passive Component
With Aghanim's Scepter Passive Spirit Spawn Interval: 1
Creep Collision Radius: Affected by AoE Radius bonuses. 150
Hero Collision Radius: 110
Explosion Radius: Affected by AoE Radius bonuses. 360
Number of Spirits: 5
Collision Damage: 10/15/20/25
Explosion Damage: 30/50/70/90 (Talent 85/105/125/145)
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 symbol
 26/24/22/20 (With Aghanim's Scepter 13/12/11/10)
Mana symbol
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. Can be activated to explode spirits.
Not disabled by Break.
Break Notes:
Upgradable by Aghanim's Scepter.
Does not disable the passive spirits spawning.
Modifiers [?]
Ability Draft Notes
Ability Draft Notes:
Spirits are replaced by their sub-abilities upon cast. Keyboard White Mouse Right Right Click toggles between Spirits In icon Spirits In and Spirits Out icon Spirits Out.
These 3 abilities share a single ability slot.
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 its 650 maximum distance upon cast.
    • The spirits always rotate clockwise and are centered around Io's location, following it wherever it goes.
    • Moving the Spirits Spirits In icon In or Spirits Out icon Out do 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 creep, illusion, or a creep-hero comes within 150 radius of the spirits, it takes the 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, dealing the explosion damage around them.
    • Successive casts instantly cause the current active spirits to explode as well.
  • Spirits provide 3-second 150 radius flying vision 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 425/525/625/725) damage to a single unit when all spirits explode on a target (before reductions).
  • Adds a passive component to Spirits, constantly and passively spawning spirits around Io with the same intervals, with the active component and effects still present.
    • Now instantly cause the current active spirits to explode upon cast.
    • The Spirits In icon Spirits In and Spirits Out icon Spirits Out sub-abilities become permanently available as well.
    • The Spirits' now has an Infinite duration and they do not explode unless colliding with heroes.
    • If the spirits did not collide with a hero for more than 6 seconds, the next explosion will deal twice the damage.
    • This is because when the colliding spirit exploded, the newly spawned spirit now takes its place and collides with the enemy hero again.
  • When acquiring Aghanim's Scepter icon Aghanim's Scepter while a cast is already active, the spirits from that cast disappear without exploding while creating new spirits.
    • When losing Aghanim's Scepter, the spirits from it disappear immediately, without exploding.
  • Spirits immediately explode upon losing the ability.
  • Spirits immediately explode upon losing the ability and while Morph icon Morphing back to original form.

Overcharge icon
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.
Attack Speed Bonus: 35/60/85/110
Max Health as Health Regen Bonus: 0.5%/0.6%/0.7%/0.8% (Talent 0.7%/0.8%/0.9%/1%)
Spell Damage Amp: 8%/10%/12%/14%
Duration: 8
With Aghanim's Shard Slow Resistance Bonus: 30%
Cooldown symbol
Mana symbol
Upgradable by Aghanim's Shard.
Aghanim's Shard Upgrade:
Grants Overcharge Slow Resistance.
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% (Talent 5.6%/6.4%/7.2%/8%) of the target's max health + 2.4%/3.84%/5.6%/7.68% (Talent 3.36%/5.12%/7.2%/9.6%) of Io's max health on the Tethered ally.
    • TALENT
      The max health regeneration increasing Talent talent does not update the current Tether instance.
  • Stacks multiplicatively with other slow resistance sources.
    • The Tethered target can also gain slow resistance.

Spirits In
Does not proc any on-cast effects when cast. DD
Spirits In icon
Calls the spirits closer to you. Can be toggled on and off.
Min Distance: 200
Cooldown symbol
Mana symbol

  • 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.
  • This sub-ability becomes permanently available.

Spirits Out
Does not proc any on-cast effects when cast. FE
Spirits Out icon
Sends the spirits farther away from you. Can be toggled on and off.
Max Distance: Affected by AoE Radius bonuses. 650
Cooldown symbol
Mana symbol

  • 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.
  • This sub-ability becomes permanently available.

Relocate icon
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 Range: Global
Effect Delay: 3.5/3.25/3
Duration: 12
Cooldown symbol
 100/90/80 (Talent 75/65/55)
Mana symbol
Partially disabled 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 canceled.
    • 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.
  • Provides a 3.5/3.25/3-second 300 radius flying vision at the targeted point.
  • 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 in any way.
  • Io may Break Tether icon Break Tether at any time to prevent bringing an ally back.
  • Destroys trees within 350 radius around Io upon both teleports.
  • Successive casts teleports Io and the affected ally to the newly selected location upon each cast, but it Relocates them back to the first point when the ability was cast.
    • Does not refresh the duration. Io and the affected ally are Relocated back after 12 seconds.


Io Innate
Not disabled by Break.
Io Innate icon
There is no description for this ability.
Effect Range: 256
Modifiers [?]

  • Io's facing direction is marked by an arc-like effect.
  • A hidden modifier causes Io to have 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.


Hero Talents
Attack Tether icon Tethered Ally's Target25+400 Health to Tether icon Tethered Units
-25s Relocate icon Relocate Cooldown20+0.2% Overcharge icon Overcharge Max HP Regen Bonus
+55 Spirits icon Spirits Hero Damage15+6% Tether icon Tether Movement Speed
+15 Attack Damage to Tether icon Tethered Units10+15% Tether icon Tether Enemy Move/Attack Slow

Recent Changes[]

Main Articles: Changelogs, Old Abilities and Hero Lore
  • Tether icon Tether
    • Now deals 10/20/30/40 damage per second coming within its slow range.
    • Has a 0.5-second damage interval.

Recommended Items[]

Starting items:

  • Tango icon Tango provides health regeneration to Io and a lane partner through Tether.
  • Healing Salve icon Healing Salve keeps Io and ally up in health during the early game.
  • Clarity icon Clarity sustains Io and ally with mana to use abilities.
  • Enchanted Mango icon Enchanted Mango gives some health regeneration, as well as mana restoration.

Early game:

  • Bottle icon Bottle, available at the Secret Shop, restores both ally's health and mana with Tether.
  • Urn of Shadows icon Urn of Shadows heals Io while Tether passes that healing to an allied target.
  • Soul Ring icon 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 Magic Wand gives attributes and a bit more amount of heal compared to Magic Stick.
  • Spirit Vessel icon Spirit Vessel, upgraded from Urn of Shadows icon Urn of Shadows, increases regeneration and healing for Io to keep allies healthy, while providing bonus health.
  • Arcane Boots icon Arcane Boots restore a large amount of mana to Io and allies with Tether.
  • Mekansm icon Mekansm heals Io's tethered partner for much more. It also provides a health regeneration aura to boost survivability.

Late game:

  • Guardian Greaves icon 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 Glimmer Cape allows Io or allied target to escape from enemies with invisibility and magic resistance.
  • Ghost Scepter icon Ghost Scepter shields Io from physical attacks, so it stays alive longer to help allies.
  • Heart of Tarrasque icon Heart of Tarrasque gives a huge amount of health and health regeneration, increasing the tethered allies' health regeneration and survivability.

Situational items:

  • Tranquil Boots icon Tranquil Boots heals Io and tethered allies more if they do not need the mana from Arcane Boots.
  • Drum of Endurance icon 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 Pipe of Insight grants aura of health regeneration and magic resistance, a great item to absorb magical damage.
  • Vladmir's Offering icon Vladmir's Offering has useful aura with many perks, including bonus attack damage and lifesteal, enabling allied physical attackers.
  • Solar Crest icon 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 Force Staff provides useful ability to position different heroes, including Io.
  • Holy Locket icon Holy Locket enhances Io's healing power, as well as strengthening its defense with bonus health and magic resistance.
  • Scythe of Vyse icon 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 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.

Dota Plus Progress[]

Main Article: Hero Challenges

Relics track a hero's actions and statistics, and display in-game notifications when a milestone is reached. They are only available to Dota Plus subscribers.

Relics Voice Lines
Relic Rare icon
Tether icon Tether Slows
Relic Rare icon
Spirits icon Spirits Damage
Relic Rare icon
Overcharge icon Overcharge Allies Duration
Relic Rare icon
Damage During Relocate icon Relocate
Relic universal icon
Damage During Tether icon Tether
Relic universal icon
Total Healing
Relic universal icon
Urn of Shadows icon Urn of Shadows Charges Used
Relic universal icon
Allies Glimmer Cape icon Glimmer Cape Duration
Relic universal icon
Dominating Kill Streaks
Relic universal icon
Dust of Appearance icon Dusts Leading To Kills
Relic universal icon
Enemy Observer and Sentry Wards icon Ward Kills
Relic universal icon
Observer and Sentry Wards icon Wards Placed
Relic universal icon
Kill Assists
Relic universal icon
Plus Hero Badge 1
Plus Hero Badge 2
Plus Hero Badge 3
Plus Hero Badge 4
Plus Hero Badge 5
Plus Hero Badge 6



  • 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.