|This article is about a/an actress in Choudenshi Bioman.|
Yuki Yajima (矢島由紀 Yajima Yuki) portrayed Mika Koizumi, the first Yellow4 in Choudenshi Bioman. Before being on Bioman she had a brief role as the character Bell Helen on the Metal Heroes series Sharivan
Although there have been other rumors on why she left the show, no one is sure what actually happened. She has also completely disappeared from the public eye, which does not help matters.