Hero Mastery

Io

A snowballing 'babysitter' support: Tether speeds up & heals your carry, and Relocate drops the two of you anywhere for a global gank or instant escape.

Mastery parameters

Your XP and damage per game against other Io players — average vs Top 20%. Supports are not graded on GPM.

Members only

Learning journey

1 Know the kit
2 Win the lane
3 Timing & rotations
4 Win the fights
5 Master

5 stages, each with one target from your own games and one short quiz. Make Io your mastery hero to start — progress shows on Home and Arcana.

Phase by phase

Laning: make your carry's life easy

You 30%Team 70%

Skills in lane — Pro supports max Spirits (W) first — 41% of 261 games since patch 7.41, then Overcharge (E). Some max Overcharge (E) first instead (31%). First talent at level 10.
Level 2 — Tether + Spirits — Your core lane combo: Tether to your carry, spin Spirits into the enemy, Overcharge for attack speed. The Spirits slow locks the kill.
Level 6 — Relocate — Relocate warps the map: take your carry to another lane for a surprise gank, then teleport back to safety before the enemy responds.

Skills 1–7

Starting items

Iron Branch36%
Gauntlets of Strength15%
Tango11%
Sage's Mask9%
Magic Stick7%
Faerie Fire6%

Pros buy this phase

Helm of the Dominator98%
Mekansm2%

The Hard Support's job this phase

Pull at minutes 2 & 4 to keep the lane from pushing — the single most important HS skill.
Harass the enemy offlaner whenever they step up for XP, but never abandon your carry.
Ward near the enemy pull camp; buy sentries to deward when your pulls get blocked.

Counters & weaknesses

Fragile hero (easy to catch)

The items that shut Io down, 3 heroes that trouble it, and your answer when you play it.

Members only

Why this way? How OpenAI Five learned

One hero, one role first
OpenAI's first bot played only Shadow Fiend, only mid, until it mastered it. Stay on Io in one role before moving on.
Small, measurable rewards
OpenAI Five was rewarded for last hits and staying alive long before it understood winning. That's why each journey stage has one number to hit.
From yourself to the team
Its 'team spirit' rose over the game: early on, look after yourself; late, play for the team. Each phase's meter shows the split.
Use proven builds
OpenAI Five's builds were hand-written, not trial and error. Start from the pro build, then experiment.

Phase items: what pros buy on this hero (OpenDota). Parameters: percentiles of players on this hero (OpenDota). Item effects checked against Valve's own item data.