Koa'ki Meiru OTK

You need Urnight, Iron Core, a level 4 monster in hand OR any monster in the graveyard (to not use Bujinki Ahashima).  Or Summoner Monk, any spell card, Iron Core, a level 4 monster in hand OR any monster in the graveyard.

Simplest combo: Normal summon Urnight, Urnight reveals Iron Core, special summon Supplier, Supplier searches for Maximus, Link Bujinki Ahashima, Bujinki makes Number 60, Number 60 summons Urnight, Urnight summons Guardian or Supplier, XYZ Dark Rebellion, Vespenate on top of Number 60, summon Maximus, activate Dark Rebellion, destroy a card with Maximus, attack for game.

It may sound like a lot of setup at first but it's incredibly consistent to pull off.  Summoner Monk works as a second Urnight and only needs 1 extra spell card for the same combo to happen just in a different order, plus he can leave you with Guardian on the field as well to negate a monster effect (Nibiru?).  Tin Goldfish makes use of Supplier to search for the missing piece for when you happen to draw into both or even 3 Supplier.  Small World can set you up into ANY of these hands.  Kaijus are there to get rid of omni-negates, Pankratops puts a monster in the grave (no longer need for Bujinki Ahashima) and gets rid of a card + is also bait, and Adventurer Token engine is there to create an omni-negate before you start your combo.

That's it really.  The fact that you only need 2 or 3 cards (at worst) means you can also run all these other defensive options to make sure your combo goes through. You could also run Ash Blossom, Crossout Designator, Instant Fusion, Millennium Eyes Restrict, Mudragon of the Swamp, and Cross Sheep for more protection + a different setup similar to Bujinki Ahashima using Cross Sheep and Instant Fusion.