"Oni" (精神 Ketsuki) is a series of Level 4 DARK Zombie monsters. Their play style revolves around detaching 1 Xyz Material from a monster on the field (either yours or your opponent's) in order to activate their effects. Each "Oni" is named/colored after the primary colors: red, yellow, and blue. Their Japanese names contain 血鬼 which likely comes from 吸血鬼 kyūketsuki "vampire", literally "blood-sucking ogre".

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