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 Insect-Type monster in your hand. If a LIGHT or DARK monster is Special Summoned in Attack Position: Change that monster to Defense Position.
Insect decks, sure. But this thing is useless in Koa'ki Meiru since it's the only Insect. (Yes, you could use Diamond Core or send Iron Core to keep it, but it's the kind of card you need up for more than a turn, so that isn't feasible.)