Clorless, Chaos King of Dark World (MZMI-EN014) [Maze of Millennia]

"Reign-Beaux, Overlord of Dark World" + 2+ Fiend monsters
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If this card is Fusion Summoned: You can destroy all cards your opponent controls. This card's original ATK/DEF each become the number of materials used for its Summon x 1000. Once per turn (Quick Effect): You can target 1 face-up card you control; discard 1 card, also your opponent cannot target that face-up card with card effects for the rest of this turn.