The vocalist was from Dio Distraught overlord.
This will be great! can't wait to here this..

After a long time 3 of the members of Dio have decided to do a session on August 6th.
They’ll be the opening act at BrainStein’s debut one man live “according to tradition”.
The session members are as follows:
Vo.mikaru (Dio)
Gu.G (the fool)
Gu.速水 (真剣組) (Gu.Hayami (gachi-gumi))
Ba.ivy (Dio)
Dr.denka (Dio)
The live will be August 6th, as I said, and will take place at Shibuya BOXX. Tickets cost 2500yen.
So if anyone is in Japan at the time, it seems like it’d be fun!