A middle-school student and Yuu's younger sister. She likes stars. She is also a huge fan of the Idol Yusa Nishimori.

Spoiler

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.

Spoiler

In episode 10, she is saved by her brother Yuu who traveled 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.