Koa'ki Meiru

Every Koa'ki Meiru monster carries the same upkeep demand: at the end of each turn it is on the field, the player must either send an Iron Core of Koa'ki Meiru from the hand to the Graveyard or reveal a matching type card, or the monster destroys itself. The entire deck is built to manage this cost without running dry. Koa'ki Meiru Supplier refills the hand the moment a Rock monster it controls hits the Graveyard, fetching another Iron Core or a card that names it. Core Compression trades a revealed Iron Core and a discarded monster for two draws, turning the upkeep cost into card advantage. Koa'ki Meiru Crusader recovers spent resources directly from the Graveyard after winning a battle, and Koa'ki Meiru Boulder searches when destroyed, ensuring the deck rarely goes without fresh copies of the core resource.

That constant supply of Iron Core powers tools that double as disruption pieces. Koa'ki Meiru Drago shuts off all LIGHT and DARK Special Summons, Koa'ki Meiru Doom negates their Main Phase effects, and the Rock suite of Sandman, Wall, Overload, and Guardian each Tributes itself to negate a Trap, Spell, Summon, or monster effect respectively. This gives the deck a heavily interactive going-first posture, threatening to answer almost any category of opposing action at no card cost beyond the monster itself. Koa'ki Meiru Tornado and Maximus add board-clearing muscle, with Tornado returning an Iron Core to the deck rather than spending it, letting the resource cycle continue while clearing away Special Summoned threats.