Chief Shizuo Chūjō leads the International Police Organization (IPO) and commands the Experts of Justice, a paramilitary force countering global threats. His operational callsign, "Silent Chuujou," mirrors his unwavering composure during missions.

Chūjō possesses an immensely devastating power, potentially exceeding that of any other Expert of Justice. Due to its extreme danger to himself and others, he is strictly prohibited from employing this ability under any circumstances.

As IPO chief, he oversees strategic operations against adversaries like the Big Fire terrorist organization. Chūjō coordinates field agents and resources while exercising high-level decision-making authority within the IPO command structure. His responsibilities include safeguarding humanity from existential threats, particularly those involving the misuse of advanced technology such as the Shizuma Drive or ancient GR units.