The Six Samurai - Irou (SDWA-EN008) [Structure Deck: Samurai Warlords]

At the start of the Damage Step, if this card attacked a face-down Defense Position monster: Destroy that monster immediately with this card's effect without flipping it face-up or applying damage calculation. You must control another "Six Samurai" monster with a different name to activate and to resolve this effect. If this card would be destroyed, you can destroy another "Six Samurai" monster you control instead.