u/LowTierVergil

Changed AC to just 20

Changed bludgeoning, piercing, and slashing resistance to just non-magic resistance

Moved a lot of his abilities over to Legendary and Lair actions so he'd have a reason to use them

Changed the Clone Attack and Multi-chops to just 5 attacks and just increased the base damage as if he's hitting multiple times

Got rid of the second half of Golden Chain as I feel like that'd really only be used outside of combat

Changed Prismatic Wings to a recharge of 6, does the damage with a save for half rather than dropping to 0, and gave an optional rule to stop the attack if the player has reaction attacks (That one was based Sonic being able to stop it by smashing his wings, it's still a very powerful ability so I wanted a way to potentially cancel it)

This is still a very powerful boss, like endgame level so he shouldn't be fought unless the party is fully prepared.

I based his attacks off his actual in-game attacks which already had damage types that exist in 5e.

The reason why nat 20s can completely avoid damage is because fighting Tabuu in the game you could outright avoid his attacks entirely and take no damage.

The Golden Chains being able to control people is based on the fact that he controls Master Hand in the Subspace storyline.

The few attacks that ignore resistance is because they were attacks that had a similar effect in the game.