An 11 year old girl that suffers from the illness that plagues the boy. Like the boy, she will die when she turns 12. To her, personal identifiers are blocked out by colorful blobs. The girl is a cheerful and friendly person, and is always nice towards the boy. She is a deeply creative person, being invested in making art throughout her days. She's also a genius that mastered all academic subjects before she turned 10.

Spoiler

The girl was born to a pair of criminals, her father being a serial killer and her mother being a serial arsonist.

Spoiler

After she dies, the girl, along with the boy, are named Shou Yamai (山井症). Their real names are unknown.