I think it is a side project to his solo where they perform reworked versions of his solo stuff.
Thing is, I have no idea who the third dude (the other apart from Yugami) is. No one I've talked to knows either. He's never mentioned. It's so weird. or maybe he is but it's really unnoticeable.
You would be right and we can crack the mystery of the third man once I get my hands on their album... that is IF the vendor ever gets back to me first. :/