Taishi Gotanda

Introduced in the prologue "Childhood," he is a film director. He looks intimidating but is actually a "kidult" who still lives in his parents' house. He took a liking to Aqua, who was at the filming site of a TV drama starring Ai, and decided to cast both Ai and Aqua in a movie, which led to Aqua's acting career. Trusted by Ai, he was asked to shoot a documentary film about B Komachi and was entrusted with a video letter addressed to the grown-up Aqua and Ruby. He also accepted Aqua's request to become his apprentice and has been helping with film production. Having known them for years, he suspects that Aqua and Ruby are Ai's children.

The films featuring Ai and Aqua have been nominated for movie awards, and his other films have also received multiple nominations, proving his directorial skills. However, he is purely focused on filmmaking, often putting commercial success second (Aqua calls him "just a big kid who happens to make movies"), which is why he remains a director of low-budget films and TV dramas.