You can Ritual Summon this card with any Nekroz Ritual Spell Card. Must be Ritual Summoned without using Nekroz of Catastor , and cannot be Special Summoned by other ways. You can discard this card, then target 1 Nekroz monster in your Graveyard; Special Summon it. You can only use this effect of Nekroz of Catastor once per turn. At the start of the Damage Step, if a Nekroz monster you control battles a face-up monster your opponent controls that was Special Summoned from the Extra Deck: Destroy that monster.