Manaka Lore:

She first learned about ballet when she was 3 and saw her cousin's ballet shoes. When doing ballet, wearing the tiara and doing the movements, she felt like she became someone else, like a princess. Back then, she was shy and introverted, lacking confidence and not talking much. But when performing, she was able to express herself however she wanted and she was able to like herself. Her dream then became wanting to become a ballerina and wear the sparkliest tiara.

However, she ended up practicing too much and injured her back, recovering enough to function in daily life but effectively ending her prospects of becoming a professional ballerina. Now without the thing that allowed her to express herself, she felt she had nothing else.

Time progresses from here and she suddenly loses her father and grandparents in an accident of some sort, though this is covered in last year's birthday stream so it's not touched upon here.

Around the time she had to take high school entrance exams, she saw Kyoko from PCS on TV (in this case she probably played SS or something) and got interested in idols being able to go onstage and perform. She was motivated again to change herself and chose to move to Tokyo to enroll in a high school there in order to work toward being an idol. Her last performance prior of this was singing to some kids at volunteer work.

The va-liv project then starts from there when she meets Ishikawa and auditions for it.