Though she came into the world thanks to a shut-in programmer named Mitsuru Tonuma, Haru ended up possessing a fish instead of the human. However, due to her inability to move on land, Haru uses Tonuma to commit murders of various women and dump them into her tank so she can devour them and adopt their attributes to look human and move about on land without trouble. Tonuma was about to feed Kaoru to Haru as the final victim when Kouga arrives and exposes Haru by destroying her tank. Suffocating as a result, Haru's final words of Kouga using Kaoru to get to her causes a rift between the two as the former kills Haru.
- Haru's human form is portrayed by miko.