Quote Originally Posted by Lemuria View Post
My guess is that despite being developed by Squaresoft, Nintendo hold the final say since the game he's in was a Nintendo product. Probably an unlikely cameo.
I think it may be the other way around. Geno, another original character from Super Mario RPG, made a cameo in Mario & Luigi: Superstar Saga and the credits for the game included "Character "Geno", reserved by SQUARE ENIX CO., LTD"

Based on that, it appears that Square holds to the rights to its original creations inside Super Mario RPG.

Normally I would be against this sort of series cross over...but I loved Super Mario RPG so much, I'd be willing to let it slide :P