Koa'ki Meiru Doom

[ Fiend / Effect ] 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 or reveal 1 Fiend-Type monster in your hand. Negate the effects of LIGHT and DARK monsters that activate during the Main Phase. ATK/ 1700 DEF/ 800