The Mayhem ability on Carnage does make him a bit awkward as a Commander himself, but he should excel in many different 99s
His Event Pack card is among the best cards to include in a blue Doflamingo deck, since his leader ability can cheat out Jinbes play cost, making him an instant threat on the board
Not only does it effectively let you have two copies of a chosen partner commander, you can also copy legendary permanents with impudence
It came about years later in Selesnya builds featuring Mastery of the Unseen as a late-game mana dump
Mega Greninja ex Deck: Precision Damage and Flexible Energy Use Mega Greninja ex may seem underwhelming due to its Stage 2 evolution, low attack damage, and modest HP
This comes in handy when opponents have interactions like Scavenging Ooze that can nullify your extraction by removing a legal target for your spell