Tsugumi Shibata

Hajime's daughter who often refers to him as "Hajime-chan". She sees Ai one day and has had a mysterious connection with her ever since. At first, she reports everything she sees through Ai to Hajime, but as the series progresses, she becomes more reluctant to do so as she begins to disagree with her father on whether they should try to stop Ai or not.

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She is briefly shown in the second season as a source of information for an investigator. At the same time, it seems that she has a similar relationship with Kikuri, which is revealed in the 24th episode of the second season. She is the medical teacher of Yuzuki's school, in 3rd seasons 20th episode it's revealed.

When first introduced, Tsugumi a 7 year old girl with brown hair and brown eyes. During this time, she would often braid her hair into two ponytails, with black hair bands and a red clip holding her bangs.

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In each season, she is shown to have grown up by a number of years. In Two Mirrors, her hair has grown up to her mid-back. In Three Vessels, she is depicted to have become an adult and retains her hair length up to her mid-back. During this time, she is often seen wearing a lab coat in Yuzuki's school, which is due to her duties in the school as a nurse. Her other attires include a pea coat and a kimono.

(Source: Wikipedia, Hell Girl Fandom)