A strange and naïve girl with a kind heart, never wanting to see someone suffer or get hurt. She is very innocent and dedicated. It is also noted that she is a beautiful singer. Despite her role as the titular character, she is a bit of an enigma within the series, as her origins have yet to be explained. She seeks to heal the heartaches of others, resulting in the filling up of a mysterious bottle called a "flask" with the suffering of those people's hearts so that someday she will be able to go to a certain place that she really wants to go. It has been implied that she came from another dimension. She seems to have no memories of her past.

Her only restriction appears to be that she cannot fall in love with anyone she heals the heart of. Curiously she also seems to not be allowed to take off her hat in public either, though this has yet to be addressed further. Kobato has a very cheerful and enthusiastic outlook in life and her wanting to aid others in need is very heartfelt and sincere. However, she can also be clumsy, rather clueless, and rash with her actions, and often trips over her own feet, much to Ioryogi's annoyance. Currently she works at the Yomogi Nursery run by Sayaka, alongside Fujimoto, where she got a job as an assistant not long after starting her task.