In a new interview with the Japanese website Nintendo Dream, Smash Bros. producer Masahiro Sakurai was asked which character he wanted to include in the latest Super Smash Bros (which just wrapped its DLC production this month) but couldn’t. Sakurai immediately mentioned Geno. In fact, he wanted Geno in the game all the way back in Brawl.
Geno is a living puppet that was introduced in the Super NES classic Super Mario RPG: Legend of the Seven Stars. Aside from a silent cameo in 2003’s Game Boy Advance title Mario and Luigi: Superstar Saga, the character has never appeared again. The leading fan theory is that Square-Enix, who developed Super Mario RPG for Nintendo, has partial ownership of the Geno character and, for whatever reason, won’t sign off on his return. This has never been confirmed, but the fact that no other original character from Super Mario RPG has made a playable return anywhere is pretty convincing evidence.
It’s not entirely true that Geno isn’t in the game at ALL. He makes a sort-of appearance in the form of a Mii Fighter costume. Apparently this was the best Sakurai could do.