Child Emperor, known as Isamu, holds the rank of S-Class Hero 5 in the Hero Association. This young boy is distinguished by his large eyes and typical attire: a plain T-shirt with both buttons fastened and a black school backpack containing his technological arsenal. Despite his youth, he possesses exceptional intellect and prioritizes education, maintaining commitments like cram school even during global crises. He exhibits frustration when others perceive him as childish. His personality is analytical and strategic. He approaches situations with calm observation, formulating detailed plans in combat and leadership scenarios. Independent and driven by knowledge, he focuses on accumulating expertise and technological mastery, often withdrawing socially to rely on his inventions. This reflects a deeper fear of helplessness, motivating his pursuit of self-sufficiency through preparedness. His combat effectiveness stems from technological prowess. His signature backpack integrates versatile tools: extendable spider-like limbs for mobility and combat, saws, hammers, gas burners, and analytical computers. It also contains layered transparent films noted for high impact resistance, though Resurrected Phoenix Man compromised these during a confrontation. One computer gadget, "Weak Point Analysis," scans opponents to identify vulnerabilities and temporarily enhances his offensive capabilities. While not primarily reliant on physical strength, he demonstrates enhanced speed, reflexes, and durability. During the Monster Association arc, Child Emperor led the Hero Association's assault on the monster headquarters. He coordinated strategies and engaged in high-stakes battles, including against Phoenix Man, utilizing his analytical mind to assess battlefield dynamics and opponent capabilities. Following the arc and the rise of the Neo Heroes, he remained affiliated with the Hero Association.