Aside from the 8 characters already presented on the main site, there's still 5 more to be revealed.
The main site says there's only three spots left to fill... So... Secret characters? :3
Already I'm feeling quite a Blazblue vibe from these guys. Already I see a Tager, a Lambda, and an Arakune.
However, the man at the very left seems like he may have just been tweaked to become Gordeau. Could be looking at only 4 characters to reveal.