What is the best way to unlock Super forms?

Spam moves that you find effective to some demons that's effective for the character you are using
Nero-Scarecrow-Spam Devil bringer until death

I'm gonna go out on a limb cause it sounds like your not even sure how to unlock them. There's only one way which is to beat DMD mode. And when or if your there USE YOUR ITEMS! I almost consider it cheating it makes the game so much easier. But also take note this makes the item collector achievement take much longer if your going for that one too.

well if you would like to know: first you need the Code Breaker CD or what ever Xbox calls it, then you need to go to that CDs website and type in the games name, and download all the cheats on to that CD that you want, and there you go..... you should be able to handle it from there.

you need to beat devil hunter mode, then son of sparda mode, then Dante must Die mode,....lot of effort.