Kai Fuzuki represents July as a member of the idol group Procellarum. Born on July 15, he stands 186 cm tall with blood type O. As the eldest of six brothers in a large family, this role shapes his approach to responsibility and group dynamics within Procellarum.

He possesses an easy-going and reliable personality, naturally assuming a supportive big brother role both at home and among his fellow group members. This temperament provides stability and security for the unit, significantly contributing to Procellarum's cohesion, especially during reflections on their growth and future.

In the lead-up to the Full Moon Festival 2020, a joint concert with sibling unit Six Gravity, Kai undergoes introspection. While acknowledged for his stabilizing presence, he privately expresses restlessness, noting a lack of recent "adventures" in his life. This feeling coincides with an encounter involving a mysterious cat, prompting concern from other members and hinting at deeper contemplations about his personal and artistic path.

His Procellarum activities extend to collaborative efforts outside main group performances. He participates in brainstorming sessions for member projects, like Rui Minaduki's piano recital promotion for the Full Moon Festival. Fellow members seek his opinions, leading to group outings that occasionally result in unexpected encounters, such as visiting a location coinciding with Rui's brother Rei at his workplace.

Glimpses of his everyday dormitory life include sharing late-night instant noodles and simple recipes with members Kannaduki Iku and Nagatsuki Yoru. These casual moments sometimes feature him in military uniform attire.

His responsibilities also encompass leadership in special projects. He was appointed team leader for a special dance group formed with members from other Tsukino Talent Production units for the "High School Dance Colosseum" event, demonstrating trust in his capabilities beyond his usual supportive function.