A young 13-year-old girl interested in gothic culture. She seems to like everything related to the horror genre, often tending to scare the other idols. Koume tends to have a cheerful disposition when it comes to horror, thinking that zombies are very cute and saying she thinks it's adorable when they trap people. She's also very shy, and bad at conversing with others. She starts as a borderline shut-in, only coming to an idol audition because her mom tricked her into going (saying they were showing a horror movie there).
However, recent cards and the anime have portrayed her as developing an odd sort of friendship with the equally socially awkward Syoko Hoshi, often watching horror movies with her.
(Source: iM@S Wiki)