Time to put on your "beary" sad faces, fighter fans: It seems that Labrys, Persona 4 Arena's axe-toting android girl is not a playable character after all. In the arcade edition of the game (which launched in Japan yesterday), she's a boss character encountered in the latter half of story, prior to the final boss fight against a character I'll name below (spoiler alert), along with some new details about the game's instant-kill finishers.
Then again, this is the arcade edition. A lot can change along the trip from game center and the game console, and in all likelihood the sexy footless metal maiden will make it onto the roster by the time it hits households.
P.S.: It seems that Labrys isn't completely new. She apparently popped up in an audio play (aka "Drama CD") for Persona 3.
It's "Final Form" Teddie! I don't know if the above is his actual form, though.
As for those insta-kill moves, they're apparently like BlazBlue's "Astral Heat" things, basically ways to just end a match in the final stages, with various preconditions in place, such as being in match point with a full SP bar. It shouldn't be cheap, at least in theory, but I'm no fighting game aficionado, so I'm in no position to judge.