Suzune Ayasaki

A mysterious spirit that initially only Hayate seems to see. For some reason, she seems determined to keep Hayate and Nagi apart by trying to free him from his ¥156,804,000 debt.

[Spoiler] Suzune is actually the spirit of Hayate's grandmother from his father's side. To make atones for the sins of her son, she had been trying to 'free' Hayate from his debt with the thoughts that that would make him happy. [/Spoiler]