Debuff
Sleep
The Champion with this debuff is unable to act X Turns. Cooldowns are not refreshed while Sleep is active. Continuous Heal, Poisons, and HP Burn work as normal while the Champion is asleep, so do any Passive Skills that heal the Champion.
This debuff can be removed from the target by inflicting any kind of active damage (except the turn when the Sleep debuff was placed).
What the game's own status effects screen says
In the game data this effect appears as Sleep.
Champions that apply it
45 champions have a skill that applies Sleep, according to the effect lines in the game data. This lists who applies it, not how reliably: chance, duration and resistance are on each champion's page.
Aeila Lifebraid
Alure
April O'Neil
Arcanist
Bambus Fourleaf
Cagebreaker
Chaagur
Chancellor Yasmin
Chronicler Adelyn
Claidna
Conellia
Crimson Slayer
Deathknight
Diabolist
Djamarsa
Edward Kenway
Eostrid Dreamsong
Fortus
Gaius the Gleeful
Harvest Jack
Hellhound
Interceptor
Kerin the Harvester
Lady Mikage
Maeve
Marquis
Muckstalker
Nell Blackteeth
Noct the Paralyzer
Orynyx Mindcrawler
Prince Kymar
Retainer
Roxam
Sabrael the Distant
Seducer
Seer
Siphi the Lost Bride
Tatsu
Tayrel
Thenasil
Theodosia the Disgraced
Ultan of the Shell
Vagabond
Valkanen
Zelotah
The description is the game's own text. It has not been tested in battle here, and the game's wording can be loose (for example about numbers that differ between versions of an effect). See Data quality for what has and has not been checked. Found a mistake? Use "Report a problem" at the bottom of the page.