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17 + 1.9
14 + 1.6
23 + 1.7
Level Base 1 16 25
Hit Points 150 473 1043 1708
Mana 0 299 650 1079
Damage 26‒35 43‒52 73-82 108‒117
Armor -2 -0.04 3.6 8.14
Attacks / Second 0.58 0.67 0.82 1.01
Movement Speed 295
Turn Rate 0.7
Sight Range 1800/800
Attack Range 575
Missile Speed 1200
Attack Duration 0.15+0.4
Base Attack Time 1.7
Collision Size 24

Io the Guardian Wisp is a ranged strength hero who works best as part of a communicative team. With its support-oriented skill set, Io is able to share its strength through Tether and Overcharge, harass enemy heroes out of the lane with Spirits, and materialize itself and an ally anywhere on the map with Relocate. Gank enemy Heroes, push undefended lanes, save teammates from deep within enemy territory—the possibilities are endless, and Io features one of the highest skill ceilings in the game.

Io, unlike other heroes, does not need to be facing towards a unit to attack, use abilities, or items. It still has a front, marked by an arc-like effect, and a back.


Io Io, the Guardian Wisp
Role: Pip roamer.png Support / Pip babysitter.png Lane Support / Pip ganker.png Nuker
Lore: Io is everywhere, and in all things. Denounced by enemies as the great unmaker, worshiped by scholars as the twinkling of a divine eye, Io 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 matter, a sentient manifestation of the charge that bind particles together. It is only in the controlled warping of these forces that Io’s presence can be experienced on the physical plane. A benevolent, cooperative force, Io bonds its strength 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.
Voice: Himself (Responses)



Partially blocked by Spell Immunity. Not blocked by Linken's Sphere. Cannot be purged. Play
Tether icon.png
Ability Affects
Target Unit Allies
Tethers Io to an allied unit, granting bonus movement speed to both. When Io restores health or mana, tethered units target gain 1.5x the amount. Any enemy unit that crosses the tether is slowed. The tether breaks when the allied unit moves too far away, or Io cancels the tether.
Cast Time: 0.001+0
Cast Range: 1800
Tether Break Distance: 900
Move Speed Bonus: 17%
Move Speed Slow: 100%
Attack Speed Slow: 100
Slow Duration: 0.75/1.25/1.75/2.25
Tether Duration: 12
Cooldown 12 Mana 40
Partially blocked by Spell Immunity. Cannot tether spell immune ally. Tether does not break if the tethered ally becomes spell immune.
The benevolent touch of Io brings strength from between the planes.


  • Has a sub-ability that lets you break the tether.
  • If Io tries to tether a unit that is 700 units or further away, Io will latch on and pull itself with a speed of 1000 closer to the target (to a distance of 300).
    • Can pull Io over impassable terrain and eventually get stuck.
    • Destroys trees within 350 radius around Io right after the pull.
    • If Io breaks the Tether while getting pulled to the tethered target, the pull will immediately stop.
    • The pull gets interrupted when Io is hit by another spell which applies Forced Movement.
    • If the pull gets interrupted more than 900 range from the tethered ally away, the link breaks.
  • When the distance between Io and the tethered target gets greater than 700, the link's visual appearance changes. At 700 it turns from teal to blue and at 800 it starts to flicker.
  • The tethered unit will benefit from Overcharge, Relocate, and from Io regenerating or replenishing health and mana.
    • Tethered units still benefit from all those effects even when turning spell immune, invulnerable or when hidden.
    • The health and mana regeneration will only be applied on the tethered unit if Io's respective pool isn't full.
    • The regeneration of any instant healing effect like Mekansm icon.png Mekansm will be applied to the tethered unit depending on how much health was replenished on Io.
    • The regeneration of any instant mana regeneration effect like Arcane Boots icon.png Arcane Boots will be applied fully to the tethered unit if 1 or more mana was replenished on Io's mana pool.
  • An enemy unit may only be slowed once per cast of Tether.
  • If an enemy Io is tethered to an invisible unit, the link is not correctly drawn for his enemies. The link draws between Io and the last known location of the invisible unit.
  • Disablehelp will prevent an allied Io from casting Tether on you.

Break Tether
Break Tether icon.png
No Target
Break the link to the tethered unit.
Cast Time: 0+0
Cooldown 1


  • Replaces Tether while Io is connected with an ally.

Blocked by Spell Immunity. Not blocked by Linken's Sphere. Cannot be purged. Play
Spirits icon.png
Ability Affects Damage
No Target Enemies Magical
Summon five particle spirits that dance in a circle around Io. If a particle collides 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 Time: 0+0
Spirits Spawn Radius: 150
Collision Radius: 70
Explosion Radius: 300
Collision Damage: 8/14/20/26
Explosion Damage: 25/50/75/100
Spirits Duration: 19
Cooldown 20/18/16/14 Mana 120/130/140/150
Io twists the particles of the universe with his unimaginable capabilities.


  • Upon use, Io gains 2 sub-abilities to control how far away the spirits orbit.
  • 5 spirits are summoned over the course of four seconds, so that the distance between each spirit is equal.
  • The spirits complete a revolution every ~2.3 seconds regardless of distance from Io. (Their angular velocity is constant, meaning that spirits move more quickly when further from Io.)
  • When a non-hero unit comes within the 70 collision radius of the spirits, it takes the collision damage.
  • When a hero comes within collision radius, the spirit explodes and deals the explosion damage within 300 radius to every enemy.
  • All unspent spirits will simultaneously detonate at the end of the duration or if recast, dealing the explosion damage to nearby enemy units.
  • Spirits provide 300 range 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.
  • Unlike most other spells, the spirits are visible to the enemy even if Io is invisible.
  • Can deal up to 125/250/375/500 damage to a single unit when all 5 spirits explode on a target (before reductions).

Spirits In
Spirits In icon.png
Calls the spirits closer to you. Can be toggled on and off.
Cast Time: 0+0
Minimum Distance: 100


  • Only active while the Spirits icon.png Spirits buff is on Io.
  • Does not interrupt Io's channeling spells upon cast.
  • Moves the spirits towards Io with 250ms. It takes 3.1 seconds from moving the spirits from max to min distance.

Spirits Out
Spirits Out icon.png
Sends the spirits farther away from you. Can be toggled on and off.
Cast Time: 0+0
Maximum Distance: 875


  • Only active while the Spirits icon.png Spirits buff is on Io.
  • Does not interrupt Io's channeling spells upon cast.
  • Moves the spirits away from Io with 250ms. It takes 3.1 seconds from moving the spirits from min to max distance.

Not blocked by Spell Immunity. Cannot be purged. Play
Overcharge icon.png
Ability Affects
Toggle Self
Io gains bonus attack speed and damage reduction, at the cost of draining a percentage of its current health and mana per second. If Io is Tethered to an ally, that unit also gains the bonuses.
Cast Time: 0+0
Current Health & Mana Cost per Second: 4.5%
Attack Speed Bonus: 40/50/60/70
Damage Reduction: 5%/10%/15%/20%
Cooldown 2
Drawing on the energy of matter from all worlds, Io begins the unravelling of time.


  • A tethered ally benifits from the damage reduction and attack speed, but only Io pays the drain in hp and mana.
  • Drains 0.9% of current health and mana in 0.2 second intervals.
  • Io and the tethered ally's effective health will be increased by 5.26%/11.11%/17.65%/25% (This will quickly diminish for Io because of the health loss).

Not blocked by Spell Immunity. Cannot be purged. Play
Relocate icon.png
Ability Affects
Target Point Allied Heroes
Teleport Io and any tethered ally to any location. After the spell expires Io and any tethered ally will return to their original location.
Cast Time: 0+0.53
Cast Range: Global
Effect Delay: 2.5/2.25/2
Duration: 12
Cooldown 90/75/60 Mana 100
Io is the embodiment of the mystery of the universe.


  • If Io is interrupted during the casting delay, Relocate will be cancelled.
    • Can be casted while Io is ensnared, but the teleport won't happen when still ensnared after the delay.
    • Disabling the tethered ally of Io won't prevent the ally from getting teleported if Io successfully teleports.
    • The returning teleportation cannot be prevented.
  • Indicators:
    • Enemies get a notification 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. Also provides small vision at that point for Io during the delay.
    • Creates a visual effect at Io's position before the teleport happens, which also is visible to everyone. This one does not provide vision though.
  • Relocate interrupts channeling spells and every current order of Io and the tethered ally both on initial teleport, and when going back.
  • If Io is Tethered to a unit, the Tether's duration will be refreshed before and after the delay before teleport.
  • Io may sever its Tether at any time to prevent bringing an ally back.
  • Destroys trees within 300 radius around Io upon both teleports.

Recommended Items[edit]






  • Io has no equipments currently.


  • Tether icon.png Tether can be used on allied heroes to get to their side with great speed, as it latches from a considerable distance.
  • Approaching a confrontation from behind will allow for easier use of Tether's slow. Positional items are also useful for this.
  • Spirits icon.png Spirits requires much practice and focus to control, and due to its high mana cost it is not advisable to use it frivolously.
  • Building Heart of Tarrasque icon.png Heart of Tarrasque or other health regen items will allow for much more liberal use of your Overcharge. Also, the regen you get from these items will heal your tethered partner, allowing you to heal allies by using Overcharge.
    • The same can be said with building a Bloodstone icon.png Bloodstone but regenerates mana instead of health which is useful to heroes with frequent mana problems. It can also be used in conjunction with other supports with healing abilities such as Witch Doctor icon.png Witch Doctor's Voodoo Restoration icon.png Voodoo Restoration
  • Remember that Tether icon.png Tether can be used on friendly creeps and summons, and in a dangerous situation Io may be able to avoid death by tethering to a lane creep, owing to Tether's large latch distance.
  • Should an emergency arise, Io may Tether to a wounded ally and then Relocate to the fountain to heal both Io and his ally.
    • You can also save the life of a crucial allied hero with this method, but it will often result in your own inevitable death when Relocate forces you to return to your original location. Be sure to break the Tether to your ally before you return.
    • The inverse of this can also work; Relocate from your fountain to the crucial ally and Tether them to bring them back. This is not always viable however, as it entails the 12 second discrepancy between Relocations.
  • If Io's team has an end-game carry such as Phantom Assassin icon.png Phantom Assassin or Faceless Void icon.png Faceless Void, his top priority becomes ensuring the survival of this hero at any cost, including his own life. Io's skillset makes him very good at doing this, and if he succeeds in preserving the life of his carry, they will eventually become hugely powerful, and most likely win the game for their team.
  • A good way to make Io cause a lot of damage with his nuke quickly is to summon the Spirits, make them get closer, and when the cooldown has ended, get close to the enemy and activate the spell again. This way, all the spirits around you will explode damaging the enemy and five new ones will appear, potentially exploding on him too. This is used best when Io is laning with someone with a good slow or stun, and when used to maximum potential (exploding all 10 spirits at maximum level) can deal an enormous burst of magical damage.
  • When ganking or escaping, always remember that Tether duration is the same as its cooldown, so it can be maintained on constantly as long as you have enough mana.
  • Though using Tether to offer bonus healing from items such as Tranquil Boots icon.png Tranquil Boots or an Urn of Shadows icon.png Urn of Shadows charge is a good idea, your Tethered ally will not gain anything if you are at full health. Using Overcharge to lower your health before using any healing items will assure you are able to pass along the boosted regeneration.
    • However, for mana, it does not matter if Io is full or not. Mana will always be transfered, regardless of Io's mana status.
  • Soul Ring icon.png Soul Ring is an excellent Item if you have Tranquil Boots so that you can give your Tethered target health regen and also the mana from using the active of Soul Ring.
  • A Bottle icon.png Bottle is good for the same reasons as Soul Ring; healing yourself and your partner in battle, and as well as giving mana.
  • Techies icon.png Techies, Templar Assassin icon.png Templar Assassin, and Treant Protector icon.png Treant Protector (with Eyes in the Forest icon.png Eyes in the Forest) synergise well with Io; while not good heroes for Io to attach himself to (see below), all offer map control which combines well with Relocate. Not to mention the demoralizing effect of Relocating a Techies in range to Suicide Squad, Attack! icon.png Suicide Squad, Attack!.
  • Although highly irregular, a skilled player could greatly benefit from an Armlet of Mordiggian icon.png Armlet of Mordiggian. The passive health regeneration synergizes well with Tether and the bonus armor combined with proper armlet toggling can allow Io to survive several situations he otherwise wouldn't. The health drain from Unholy Strength can also be used to lower one's health without draining their mana as overcharge would. However, an Armlet should only be considered if someone on Io's team has already purchased a Mekansm icon.png Mekansm or if other conventional items would be less useful.

Io Partners[edit]

The most common playstyle for Io is to be partnered with a Carry, preferably one with mobility or health regen issues (as Io can help make up for both). Although any durability-focused carry can benefit from Io's support, among the better known Io Buddies are:


  • 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.
  • Wisp is the name of an Elemental from the Legend of Mana series, which has a similar appearance and is usually involved in healing.
  • 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 occuring from sharply pointed structures.
  • Enigma icon.png Enigma, Io icon.png Io, Keeper of the Light icon.png Keeper of the Light, and Chaos Knight icon.png Chaos Knight together represent the four fundamental forces of the universe with Io representing the electromagnetic force, as alluded to in his lore as the force that binds all matter together, as well as his abilities which mostly rely on being bound to a partner to achieve maximum effect.

Update History[edit]

February 04, 2015 Patch

  • Fixed Blinking while in the initial Tether pull causing the Tether range to be larger than intended.

November 18, 2014 Patch

  • Fixed the mechanism Armlet of Mordiggian icon.png Armlet of Mordiggian and Overcharge icon.png Overcharge to use proper health modification (meaning their health manipulation is now completely unaffected by anything).

July 18, 2013 Patch

June 14, 2013 Patch

  • Fixed Relocate icon.png Relocate not being interrupted if Io was only disabled in the cast time but not when the teleportation happened.
  • Fixed Relocate icon.png Relocate not getting interrupted by Root debuffs (Ensnare (Naga Siren) icon.png Ensnare, Overgrowth icon.png Overgrowth, etc).
  • Fixed Relocate icon.png Relocate not revealing Fog of War for enemies.
  • Fixed Relocate icon.png Relocate not showing the initial visual effect on the ground for enemies (only showed ping).
  • Fixed being able to return creeps with Relocate icon.png Relocate by Tether icon.png Tethering a creep after relocating.
  • Fixed Overcharge icon.png Overcharge missing a 2 second toggle cooldown.

March 28, 2013 Patch

  • Wisp name change to Io icon.png Io.
  • [Undocumented] Io icon.png Io changed back to blue from teal.

March 21, 2013 Patch

March 14, 2013 Patch

  • Fixed Tether icon.png Tether sometimes ending prematurely if Relocate icon.png Relocate was cast before Tether icon.png Tether.
  • Fixed Relocate icon.png Relocated units sometimes walking away to do a previous order.

December 06, 2012 Patch

November 08, 2012 Patch

September 21, 2012 Patch

August 02, 2012 Patch

July 19, 2012 Patch

July 12, 2012 Patch

July 05, 2012 Patch

June 28, 2012 Patch

Balance Changelog[edit]


  • No longer requires turning to perform any actions.





  • Increased Overcharge icon.png Overcharge health/mana cost over time from 2.5% to 3.5%.
  • Tether icon.png Tether regeneration transfer now heals the Tethered unit at 1.5x the rate of Io.



  • Increased Base attack damage increased from 16-25 to 26-35 (total damage is now 43-52).
  • Increased Attack range from 525 to 575.
  • Tether icon.png Tether
    • Reduced Movement speed bonus from 15%/20%/25%/30% to 20%.
    • Rescaled Stun duration from 1/1.25/1.5/1.75 to 0.75/1.25/1.75/2.25.
  • Spirits icon.png Spirits
    • Oscillation subabilities no longer interrupt Io's movement.
    • Now circle slightly faster when there are fewer alive.
    • No longer slow.
    • Increased spirits duration increased from 16 to 19.
    • Reduced spawn interval from 1.2 to 0.8 (all 5 spirits now spawn within 4 seconds, instead of 6).
  • Overcharge icon.png Overcharge
    • Reduced attack speed bonus from 60/80/100/120 to 40/50/60/70.
    • now also grants 5%/10%/15%/20% incoming damage reduction towards all damage types.
    This effect also transfers to the tethered ally.Reworked:



  • Reduced Tether icon.png Tether Stun duration from 1.25/1.5/1.75/2.0 to 1/1.25/1.5/1.75.
  • Increased Relocate icon.png Relocate cooldown from 80/60/40 to 90/75/60.



  • Created.


See Also[edit]