Keyblade Wielder Perry the Platypus
Why I remember Kingdom Hearts after seen the Phineas and Ferb Star Wars Special? Because Kingdom Hearts is becoming a pseudo star wars! REALLY! The Keyblade Master Order is basically the same idea of the Jedi Order. And, hell, Kingdom Hearts Chi is basically the presequel trilogy.
The kind of story we already know about Kingdom Hearts III, includes King Mickey and Riku going around re-recruiting the biggest amount of Keyblade Masters to fight in the final fight against Xenahort. I think would be a pity if they don’t put some Disney Characters as Keyblade Masters for the occasion, so, I’m going to pitch someones while I’m working on the Palette thingie.
Now, I think, if we put this as a companion piece Perry would ask Mickey to make him a Keyblade Wielder so he can help getting his world back. Basically, I think Phineas and Ferb are building a Gummi Ship for going back to their world from Radiant Garden, but their world went destroyed. When Perry knew keyblade masters could fix that, he decided to step in and help.