If you control "Supreme King Z-ARC": Destroy as many monsters you control as possible, except "Supreme King Z-ARC", and if you do, Special Summon up to 4 "Supreme King Dragon" monsters with different names from your hand, Deck, Extra Deck, and/or GY, ignoring their Summoning conditions. You can banish this card from your GY, then target 1 "Supreme King Dragon" Xyz Monster you control; attach 2 "Supreme King Dragon" monsters from your GY and/or face-up from your Extra Deck to it as materials.
