Woah woah... having non marketable characters (as in characters without any prior mind share with the audience) is NOT the same thing as having a non-marketable game.
You can have a successful new IP fighting game with brand new characters if the visuals, the fighting system, the marketing and single player/online components are there. Games like Tekken and Soul Calibur started out this way as well, Tekken was really nothing more than a VF copy and SC was a Tekken with weapons. I mean who the hell knew about Heihachi and Ivy when those games first came out?
I am just saying you cannot put up Valentine on posters or in front of ads and expect to sell the game on the character alone. It's not the same as a Smash or a Marvel game where you can just spam Ryu, Wolverine, Dante, Mario and get free sales. Games like Smash/Marvel generate hype on roster alone, like people make decisions to buy/not buy the games based on which of their favorite characters made the cut.