In the interview when asked who Blizzard would love to see make an appearance in Super Smash Bros. Ultimate, senior producer Pete Stilwell said, “Personally, yeah, I’d love to have Diablo. That to me is the immediate one. Then if we had over time, eventually the heroes, go through all of them…or you could go really awesome and only have Deckard Cain.”
They were also asked which Nintendo characters they wouldn’t mind seeing in their games, in which Stilwell stated that Pig Ganon would be a cool addition, while associate producer Matt Cederquist said, “Bowser, Bowser would be a sweet dungeon boss.” Of course these are just ideas being tossed in the air and there’s no guarantee that it will happen.
However with Diablo 3 on the Switch, there is already a bit of a crossover as the game on the Switch will come with an armor transmorg that lets players recreate Ganondorf’s look, the Cucco companion pet, and a Triforce portrait frame.