Me too, I so hope it.. I can already imagine her entering the fight and it fills me with satisfaction. I
I've also been trying to look for any hints they could've potentially dropped in any of the Castlevania trailers.. nothing seemingly substantial.
The only "thing" (I'm not even gonna call it a hint) I was able to find (and prepare to stretch for this reach) is that when Castlevania Medusa gets angry, her eyes turn a bright orange and yellow, just like our KI Medusa's true form (or when she shoots a laser out of her eyes). It very most likely means nothing at all, but as a spectator I'm trying to look at all the details because that's just fun. Orange and yellow are intense colors and make it look more evil than say blue, so there's definitely nothing more to this. But I wanted to share it anyway lol.
Actually, another thing that caught my attention (and this is likely still a reach) is that on the Smash Blog they showed the Castlevania stage one day, right? They showed one screen of the stage as a whole, and one screen of Medusa in particular.. doesn't it seem at least slightly odd that they would show Medusa only? I mean, maybe she's just that significant of an enemy in the games that it's very recognizable to the fans (I have no idea, never played Castlevania), but why show just Medusa? Like why not Dracula? Or several other monsters? This probably means nothing as it seems too obscure, but you never truly know it with Sakurai. In another screen Isaac seemed to have been hinted at, so he might very well be doing the same here (though still most likely not, please don't attack me lol). People haven't really talked about this it seems, as it's just too vague, but I wanted to bring it up anyway. If it has been talked about on here before, then my apologies for bringing it up again lol