Umino Natsuki

is a second-year student at Hanasakigawa Girls' High School. She is the vocalist and lead guitarist of the band CHiSPA and is friends with Yamabuki Saaya, who is CHiSPA's ex-drummer. She was in the same class with Ichigaya Arisa during their first year.

Background
In Episode 26 - Kizuna Music♪, Natsuki was shown watching Poppin'Party's live concert at Live House Galaxy and waving her glowstick while they were performing  Dreamers Go!