- Nickname: Yuyu
- Birthday: November 5, 1998
- Age: 20
- Height: 168cm
- Joined: November 2016
- Previous Groups: SiS
- Previous Names: Terayama Yufu (Audition name) / Sion Sono (SiS name)
- Lyrics Written: Dreamer, Jealousy Marionette, PALET, Peninsula, I need you I love you I want you, Are you kidding?
- Member Colour: Purple
During the BiS reformation audition, she mentioned that she is bisexual.
Alongside this, during the reformed BiS’s first appearance on 矢口真里の火曜The NIGHT in 2016, they told a story from the time of the audition. They deliberately didn’t mention any names, but they spoke about one of the candidates, who was bisexual, who came onto Aya Eightprince one night. The girl spoke about being bisexual, how she likes men and woman, and then asked Aya if she wanted to try anything with her. The other members on the show alongside Aya (Pour Lui, Gozeela, Kika) also mentioned what they noticed about this person – that they kept saying how cute Aya was, and all of the other auditionees, and Pour Lui even insinuated that this person may have come to the audition with other intentions. At this time, Yuuka was a part of SiS, which may be why they didn’t say a name, or even describe the person they were talking about.
She loves otters and some fans say she resembles one.
She originally auditioned for the BiSH 2016 summer audition and was later invited to the join the BiS training camp. After not being successful at either, she was later placed in SiS before the group was merged with GANG PARADE.
Starting November 20, 2018, Yuuka has started to write her very own weekly movie review for the online publication Storywriter.