The obvious answer seemed to make a split card made up of split cards
252 side-loading slots, thick leather over a structured cover, a full-perimeter zipper that seals out everything your collection doesn't deserve to touch

Azra Smokeshaper Biting-Palm Ninja Dark Leo & Shredder Dokuchi Shadow-Walker Dokuchi Silencer Elektra, Daughter of the Hand Fallen Shinobi Foot Elite Foot Mystic Foot Ninjas Heroes in a Half Shell Ingenious Infiltrator Ink-Eyes, Servant of Oni Inkrise Infiltrator Karai, Future of the Foot Kotose, the Silent Spider Krang & Shredder Masterful Ninja Mukotai Ambusher Nashi, Moon Sage's Scion Nashi, Searcher in the Dark Nezumi Prowler Ninja Ninja of the Hand Ninja of the New Moon Okiba-Gang Shinobi Orochi Soul-Reaver Oroku Saki, Shredder Rising Overt Operative Satoru Umezawa Satoru, the Infiltrator Shark Shredder, Killer Clone Shredder, Shadow Master Shredder, Unrelenting Silent-Blade Oni Silver-Fur Master Skullsnatcher Splinter, Hamato Yoshi Splinter, Radical Rat Splinter, the Mentor Super Shredder Tatsunari, Toad Rider Throat Slitter Throatseeker Undead Hand Ninja Yuriko, the Tiger's Shadow Yuriko, the Tiger's Shadow

This ability triggers every time you take the initiative, but more importantly for us, it also triggers at the beginning of your upkeep
As if that wasnt enough, your opponents cant do much against this Son Goku since it isnt affected by the skills of cards other than Battle cards, making it difficult to remove despite the absolute need to get rid of it