Hideaki is a sentient computer program, taking the form of a holographic projection of a young boy with violet hair and pink eyes. He is a creation of the organization RI-ON, designed to appear as an innocent Dragon Drive player from Earth whose machine had malfunctioned.

His true nature is that of a digital life-form, existing solely within the Dragon Drive game and the world of Rikyu. Hideaki initially deceives Reiji Ozora and his friends, claiming to be a powerful Dragon Drive champion and, to Kohei Toki, pretending to be his younger brother. This allows him to gain their trust to further RI-ON's plans, ultimately betraying them to reveal his allegiance to the organization.

Hideaki holds a deep admiration for Meguru and is consistently motivated by a desire to prove his strength to her. His role in the story is that of an antagonist who later seeks redemption. He is instrumental in the plans of Kohei and his father, Saizou Toki, at one point being ordered to help release the powerful creature Shinryu from the D-Zone.

A pivotal moment in Hideaki's development occurs when Kohei discovers and reveals the truth of his existence: that he is merely a computer program, created only to be a tool for RI-ON, with Saizou having no genuine care for him. When Hideaki refuses to believe this, Saizou deletes him from the Dragon Drive program, seemingly ending his existence. However, Hideaki ultimately manages to return from deletion to aid Reiji and his allies in their final battle against Kohei and Shinryu. Following this conflict, he bids farewell to Meguru and chooses to remain within the digital world of Dragon Drive.

As a program, Hideaki's notable ability is his existence as a virtual life-form, which allows him to manipulate and operate within the digital spaces of the Dragon Drive game and Rikyu. His capacity to be deleted and later return underscores his nature as non-human data, marking him as a unique entity within the story's setting.