Mafuyu Suzuhara

Mafuyu is a year younger than Yuuta and attends a different college. Yuuta was the boy who rescued little Mafuyu when her classmates were bullying her long ago. She's secretly liked him ever since, and that pushed her to start stalking Yuuta. She likes him so much that she seems to have a habit of doing things that others would consider extreme...

(Source: doujinshi's character introduction)