As before the graduation, the 4th Gen was just officially released :

Rin Euka 

Rin was a model at a a clothing store. Now, she has become and trainee and entered Superiur Muses as a 4th Generation.

Sera Volswageen

Half- japanese one fourt russian one fourth swedish

Sera is the daughter of former Miss Universe Elve Kische- Volswageen.  Sera has a younger sister Zerin.

Aika Momosu:

Aika is a half-japanese half-korean trainee who was raised in Shanghai. She was supposedly to be in the duo Evescue with co- gen Kei Retsu. 

Kei Retsu

Kei is actually a full Korean yet she was born in Tokyo and was raised there. Her Korean name is Ha Yun Ji.. She also had to be in a duo with Aika Momosu.