Niimi Sora

"You're not half as nice to me as you oughta be, Nii-ni."

Kakeru's cheeky younger sister, a first-year student.

Sora spends most of her spare time hanging out at the protagonist's apartment, often threatening to move in and sometimes making him treat her to dinner. She has a selfish side, but her dedication to her brother is undeniable. She enjoys teasing Miyako for her overly-serious demeanor and occasional slip-ups.

When Sora awakens to her powers, she begins cooperating with Miyako and her brother on the investigation.

Hobbies: Playing (games, exercising, anything)
Likes: Everything fun
Dislikes: Being bored

Spoiler

She is a user, and her artifact is a bracelet. She can erase people, objects, and herself, or in other words, make them invisible temporarily. However, it doesn't affect powerful beings or users with strong Defend-type artifacts. If she forces herself to erase something until it loses its existence, her power may go out of control and potentially slowly erase her from this world.