Hey look, it's Zack "The Frozen-Star", making a comeback!
Actually, he is not...he's not in the music buisiness anymore...He lost his passion for his hobby and everything related to it. The relationship between him and Hisui has also fallen quite a bit after he went into a depression phase upon realicing he didn't get further with his music. What he does in the near future is uncertain.
Note: for those that doesn't know, Zack has Cryokinesis
Zack (c) Me