The news gives credence to rumors that Ken Amada, Persona 3's youngest (human) protagonist, also features in the Ultimax roster. As Siliconera reported, a now-baleeted Best Buy listing noted both Ken and Rise as playable in Ultimax. It also mentioned a total of six newbies, indicating there's another fighter we've yet to hear anything about. We'll likely find out soon enough, given the game is due to hit PS3 and Xbox 360 sometime this fall.
Persona 4 Arena Ultimax