Sidequest: Hunt the Mark // Yiazmat, Ultimate Mark

Commander is where Sidequest: Hunt the Mark // Yiazmat, Ultimate Mark makes the most sense — token-generating commanders can tick the quest counters incidentally, and a free 17/17 that forces opponents to split attacks across all creatures they control warps combat math in a multiplayer game. In 1v1 formats like Modern and Pioneer it's a slower proposition: the quest condition is harder to complete without a dedicated sacrifice or token engine, and paying five mana for Yiazmat after setup is just a big vanilla threat in a format full of cheap interaction. Legacy and Vintage have enough enablers to fire the quest quickly, but better payoffs exist at that power level, so it won't see meaningful play there.