During each of your End Phases, destroy this card unless you send 1 "Iron Core of Koa'ki Meiru" from your hand to the Graveyard. You can Tribute Summon this monster by Tributing 1 "Koa'ki Meiru" monster. This card cannot be destroyed by the effects of Trap Cards. During battle between this attacking card and a Defense Position monster whose DEF is lower than the ATK of this card, inflict the difference as Battle Damage to your opponent.