Ayumi is Yuu's little sister. She likes stars. She is also a huge fan of the Idol Yusa Nishimori.

She awakens the ability to make everything around her collapse, but ultimately, this awakening leads to her death. In episode 6, during a lunch break at school, Ayumi is threatened with a box cutter by a jealous classmate; she begins to run, but is soon cornered. Instinctively, she uses her ability, which collapses both the roof above her and the floor below; killing her.
In episode 10, she is saved by her brother Yuu who travelled back in time using their brother Shunsuke's ability of time leap. Her ability was plundered by Yuu after he had time leaped backwards, so she no longer has the ability.