It's no different than any other costume. Play online or beat single player modes. Play them in Tag to get two costumes at a time.
Free Step Dodge
CyberEvil
GodlyHades
Alright thank you Cyber!! Are you playing it on PS3 or XBOX? How are you liking the netcode?
CyberEvil
I play on 360 and it's fine. Seems better than 5 for sure. Handles lag better. Not perfect but it is an improvement.