- Current Name: Yashiro Yuka / ヤシロユカ
- Birthday: March 18
- Age: Unknown
- Joined: Founding member
- Lyrics Written: MONSTERS, TOUMIN SHOJO, Lonely girl
- Left: Before debuting due to anxiety
Yukako was one of the founding members of BiSH, however she never debuted due to anxiety. She left after recording their debut album, so other members had to re-record over her parts. However, her original vocals were left on the track [Spark]. She is also credited on the album as writing the lyrics for [MONSTERS], [TOUMIN SHOJO] and [Lonely girl]
From 2008 – 2015, she was the vocalist and guitarist for the band MIKINORME / 魅起法則, under the name Yashiro Yuka. Following her leaving BiSH, she reformed the group, as the sole member, under the name of mikinorumu / ミキノルム.
She also went onto form another band, SCARLET OVERKILL YOU in 2016, but there is not much information out about them.
She now makes YouTube video and often posts pictures on Twitter and Instagram of her adorable cats.