Koa'ki Meiru Doom (BP03-EN058) - Battle Pack 3: Monster League 1st Edition

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. Effects of LIGHT and DARK Monsters that activate during the Main Phase are negated.