Also Trish and Vergil, for a total of five characters (along with original DMC4 heroes Nero and Dante) - but Lady! Awesome. Here, have a trailer.
"Lady, who is a playable character for the first time in the series, has a fighting style that is conceptually quite different from that of the other DMC4 characters, with a special emphasis on firearms. Lady’s focus on long-range fighting will feel like a completely different way to take on the action."Kewl.