Gem-Knight Master Diamond (BLMM-EN143) - Battles of Legend: Monster Mayhem 1st Edition

3 "Gem-Knight" monsters
Must first be Fusion Summoned. Gains 100 ATK for each "Gem-" monster in your GY. Once per turn: You can banish 1 Level 7 or lower "Gem-Knight" Fusion Monster from your GY; until the End Phase, this card's name becomes that monster's original name, also replace this effect with that monster's original effects.