Brotherhood of the Fire Fist - Rhino

If a "Fire Fist" monster you control attacks or is attacked, during damage calculation (in either player's turn): You can send 1 face-up "Fire Formation" Spell/Trap Card you control and 1 "Fire Fist" monster from your hand to the Graveyard once per battle; your attacking/attacked monster gains ATK equal to the original ATK of the monster sent to the Graveyard, during damage calculation only.

Beast-Warrior FIRE Effect Monster 4 effect