Io, the Guardian Wisp, is a premier Strength-based support and force multiplier in DotA 1, defined by unparalleled utility and global map control. Despite being a Strength hero, Io functions as a ranged backline tether that links its life force directly to a core ally. By drastically amplifying an ally's attack speed, mitigating incoming damage, multiplying resource regeneration, and orchestrating instant cross-map teleports, Io turns any chosen ally into a terrifying global threat.
Base Stats & Attributes
Hero Attributes
| Attribute |
Base Value |
Growth (per level) |
| Strength |
17 |
+3.0 |
| Agility |
14 |
+1.6 |
| Intelligence |
23 |
+1.7 |
Statistics & Mechanics
| Statistic |
Value |
Mechanic |
Value |
| Damage |
39-48 |
Base HP Regen |
0.25/s |
| HP |
540 |
HP Regen |
+1.95/s |
| MP |
326 |
MP Regen |
+1.16/s |
| Armor |
3 |
Turn Rate |
3 |
| Move Speed |
280 |
Base Attack Time (BAT) |
1.7 |
| Attack Range |
575 (missile speed 1200) |
Attack Animations |
0.15 / 0.4 |
Hero Skills Breakdown
1. Tether
Tethers Wisp to an allied unit, granting both bonus movement speed. When Wisp restores HP or MP, the tethered target gains a multiplied amount. Any enemy unit crossing the physical tether gets slowed. Wisp will automatically pull himself to the target if they are further than a set range away. Tether breaks if the distance grows too large.
- Regeneration Multiplier: $1.5\times$ of all HP or MP gained by Io is transferred to the ally.
- Max Tether Break Distance: 1800
- Pull Threshold: Automatically pulls Io to the target if cast from further than 300 range away.
| Level |
Move Speed (MS) Bonus % |
Enemy Movement Slow % |
Cooldown |
Manacost |
| 1 |
8% |
8% |
12 sec |
40 |
| 2 |
11% |
16% |
12 sec |
40 |
| 3 |
14% |
24% |
12 sec |
40 |
| 4 |
17% |
32% |
12 sec |
40 |
2. Spirits
Io summons ancient Spirits over the course of a few seconds; the Spirits dance around Io in a circle to protect him. If an enemy hero moves close enough to touch a Spirit, the Spirit releases its life energy in a burst, damaging all enemies in an area of effect. Non-hero units only take minor damage upon touching a spirit and do not cause them to explode.
- Damage Type: Magical
- Explosion Area of Effect (AoE): 300
- Spirit Count: 5 Spirits spawned over 4 seconds.
- Scepter Upgrade: Spawns Spirits around you constantly.
| Level |
Hero Damage (Magical) |
Non-Hero Damage (Magical) |
Cooldown |
Manacost |
| 1 |
30 |
10 |
26 sec |
120 |
| 2 |
50 |
18 |
24 sec |
130 |
| 3 |
70 |
26 |
22 sec |
140 |
| 4 |
90 |
34 |
20 sec |
150 |
3. Overcharge
Io draws on more energy than he can safely handle, granting him bonus attack speed and damage reduction. If Io is tethered to an ally, the bonuses are also granted to that ally.
- Targeting Mechanic: Buffs Io individually; shares the identical buff to an ally exclusively while a valid Tether connection is active.
- Duration: 8 seconds
| Level |
Attack Speed Bonus |
Damage Prevention % |
Cooldown |
Manacost |
| 1 |
50 |
5% |
18 sec |
40 |
| 2 |
80 |
10% |
18 sec |
60 |
| 3 |
110 |
15% |
18 sec |
80 |
| 4 |
140 |
20% |
18 sec |
100 |
4. Relocate
Io temporarily relocates himself, along with any tethered hero, to the target location for a set duration. There is a casting delay and the enemy has visual indicators of the teleport.
- Duration: 12 seconds before automatically returning to the original casting point.
- Mechanic: Teleports Io and an active tethered hero partner globally to any visible or fogged area of the map.
| Level |
Teleportation Delay |
Cooldown |
Manacost |
| 1 |
3.50 seconds |
90 sec |
175 |
| 2 |
3.25 seconds |
75 sec |
175 |
| 3 |
3.00 seconds |
60 sec |
175 |
Item Build Guide
| Phase |
Recommended Items |
Strategic Purpose |
| Early Game |
Tranquil Boots, Magic Wand, Urn of Shadows |
Tranquil Boots provide cheap, massive health regeneration that Io directly duplicates to his tethered partner at a $1.5\times$ rate. Urn charges allow Io to burst-heal an ally from the brink of death mid-fight. |
| Core Items |
Mekansm, Glimmer Cape, Bracer |
Mekansm acts as a dual-layer restoration engine; activating it heals Io and nearby units, while Io's tether partner receives a massive extra injection of health because of the $1.5\times$ conversion multiplier. |
| Late Game |
Heart of Tarrasque, Aeon Disk, Lotus Orb |
Heart of Tarrasque breaks the game mechanics by giving Io permanent, non-stop fountain-like health regeneration. This completely flows to the tethered core ally, making them nearly impossible to kill. |
Quick Gameplay Tips
- The Broken Fountain Regen Interaction: Because Tether multiplies all regeneration by 1.5x, Io should actively keep its own health and mana pools below 100% when tethered. Use Overcharge or take minor creep damage to ensure you can continuously utilize items like Healing Salves, Bottled Water, or Mekansm to pass massive, continuous resource pools straight to your carry.
- Tether Pulling for Vertical Flight: You can use the long-distance targeting of Tether to cross impassable terrain or escape ambushes. By placing Tether on an allied unit or creep situated across a cliff side or forest clump from 1800 units away, Io will rapidly pull itself directly over the obstacle, leaving pursuers stranded behind.
- Relocate Extraction and Save Tactics: Relocate has a hard-coded 12-second return window. If an allied core is caught deep in enemy territory or under a tower siege, cast Relocate from your fountain to their position, quickly grab them with Tether during the teleportation delay, and the game engine will safely pull both of you straight back to the absolute safety of your fountain base.