Debuff
Fatigue
Champions under a Fatigue debuff will receive a Sleep debuff for 1 turn after using an active skill.
If a Champion with a Fatigue debuff uses a skill that removes debuffs, the Fatigue debuff will be removed and the Sleep debuff will not be placed.
What the game's own status effects screen says
In the game data this effect appears as Fatigue.
Champions that apply it
1 champion have a skill that applies Fatigue, 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.
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.