In episode one, Kouta is the main character along with Mai Makihara. He is very fond of her and helps her home every day due to her health condition.
One day, they find an abandoned kitten and Mai convinces Kouta to adopt it, naming it Blue. When Mai collapses on her way home from the shrine, partially because Kouta was not present to help her, Kouta blames Blue for her death. He tells Momo to take Blue's soul away as revenge for Mai, but stops her last second and grabs the young kitten, holding him dearly in his hands. He then speaks to Mai's soul and as a final promise, agrees to take care of Blue for her. She then passes on as Kouta is left with Blue in the park.
Kouta re-appears in episode 5, this time shown closer to Momo than in Episode one. He appears to have met her several times in between the episode gaps and also gained the ability to see ghosts, since Momo had touched him. He's told this ability will slowly disappear as he turns into an adult. Kouta helps the girl in Episode 5 by aiding her in finding her sister's soul in the school. He's shown as a much more apathetic person, and even states that he had been unable to smile since the day Mai passed away.