Sekenre
actually, unless they changed it, that isn't Dante. Its a human with a demon possessing his arm. I haven't actually seen the clip you posted but thats what i remember reading.
The guy your thinking of is nero, and he is in a blue coat. The clip that I posted is with dante, and it has been confirmed that he will be a playable character. That clip is just to show off dantes moves, which have been improved. And now you can switch between all the combat styles that you start off with in DMC 3.
If you pay close attention to the trailer you will notice at the top left hand coner of the screen. Right next to the green life bar there are 4 letters. T on the top, S on the right, G on the left, and R at the bottom. There set up like a cross, and by pressing the corrisponding button on the D-pad you can switch styles in game.