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 Zombie-Type monster in your hand. If a "Koa'ki Meiru" monster you control would be destroyed by battle or by a card effect, you can remove from play 1 "Koa'ki Meiru" monster in your Graveyard instead.
Reveals your hand for cost / Sends from hand to Graveyard for cost
Banishes from your Graveyard
Destroys itself / Cannot be destroyed by card effects
Cannot be destroyed by battle
Relatively new player to this game, so trying to understand the second effect of this card (If a "Koa'ki Meiru" monster you control would be destroyed by battle or by a card effect, you can remove from play 1 "Koa'ki Meiru" monster in your Graveyard instead"). Does this mean if you have multiple Koa'ki Meiru monsters on the field and you have some in your Graveyard, you do not have pay the maintenance cost of those monsters? Assuming that "card effect" applies to the card effects of the Ko'aki meiru monsters as well.
Yes, you can use Ghoulungulate's effect to prevent multiple "Koa'ki Meiru" monsters from destroying themselves during the End Phase. You can even banish a "Koa'ki Meiru" monster from your Graveyard to prevent Ghoulungulate itself from being destroyed.