Dark Requiem Xyz Dragon (OP15-EN002) - OTS Tournament Pack 15 Unlimited

3 Level 5 monsters
If this card has "Dark Rebellion Xyz Dragon" as Xyz Material, it gains these effects.
- Once per turn: You can detach 1 Xyz Material from this card, then target 1 face-up monster your opponent controls; change its ATK to 0, and if you do, this card gains ATK equal to that monster's original ATK.
- During either player's turn, when your opponent activates a monster effect: You can detach 1 Xyz Material from this card; negate the activation, and if you do, destroy that card, then you can Special Summon 1 Xyz Monster from your Graveyard.