Ruler of the End of the World

“You can Ritual Summon this card with an "End of the World" card. This card's name becomes "Demise, King of Armageddon" while in the hand or on the field. You can only use each of the following effects of "Ruler of the End of the World" once per turn. You can reveal this card in your hand, pay 2000 LP, then banish 1 Ritual Spell from your Deck; apply that card's activation effect that Ritual Summons a monster. You can pay 2000 LP; destroy all other cards on the field, then this card gains 2900 ATK.”