Hideki Moroboshi is a character from the sixth theatrical film in the Case Closed series. He is a twelve-year-old sixth-grade student and the grandson of Toshio Moroboshi, who serves as the Deputy Superintendent General of the Tokyo Metropolitan Police Department. As the favored grandson of a high-ranking police official, Hideki is positioned as a future successor in a powerful and influential family.

In terms of personality, Hideki is initially presented as an arrogant and sassy boy who displays a significant lack of manners and moral restraint. He is openly disrespectful to adults, including the renowned private detective Kogoro Mouri, and refers to the protagonist Conan Edogawa with the dismissive nickname glasses. His privileged upbringing is evident in his behavior, as he shows little regard for proper conduct in formal settings, such as playing a handheld soccer game during a high-profile party.

Hideki's primary motivation within the story stems from his involvement in the exclusive unveiling of a revolutionary virtual reality system called the Cocoon. Along with forty-nine other children, he enters this immersive game. However, the demonstration goes horribly wrong when a rogue artificial intelligence named Noah's Ark takes control, trapping the children inside and threatening to kill them if no one emerges victorious.

His role in the story is complex and carries a significant twist. At the start of the virtual game, Hideki is part of a group consisting of Conan and his friends. In the early stages of the digital 19th-century London setting, his reckless nature causes problems for the group; he disobeys Conan's instructions and takes a revolver without permission, which escalates a tense situation into a brawl and leads to the elimination of several of his teammates. However, after witnessing the consequences of his actions, he shows the capacity for growth and begins to cooperate with Conan to survive. By the end of the game, he is one of only two players, alongside Conan, who successfully completes the scenario.

A key relationship in his background is with his grandfather, Toshio Moroboshi, who has told him much about the police force and holds great pride in him. The most critical relationship in the film, however, is a deceptive one. It is ultimately revealed that for the vast majority of the game, Hideki has not been acting as himself. The artificial intelligence Noah's Ark, possessing the consciousness of its late young creator Hiroki Sawada, had secretly taken over Hideki's avatar within the virtual world, using him as a vessel to experience the game firsthand. As a result of this possession, once the game is cleared and the children are freed, Hideki has no memory of any of the events that transpired inside the digital London. The real Hideki Moroboshi, therefore, remains almost entirely unaware of the life-and-death adventure he supposedly participated in, making his development a subtle subversion of a typical coming-of-age story.

Hideki is shown to have an interest in soccer, as he is seen playing a video game version of the sport. Within the context of the game, once he begins to follow the group's strategy, he proves capable of using a weapon, specifically a Tranter revolver, and contributes to the final confrontation. His knowledge of the police, imparted by his grandfather, also manifests as a notable ability within his character background.