Major, whose real name is Hitoshi Mukai, operates as a member of Alice's NEET Detective Team. He maintains university enrollment primarily to access library resources for research, rarely attending classes. Despite his university status, his appearance resembles an elementary-school boy.

A dedicated military enthusiast, he invests significant time in survival games and is frequently seen in camouflage attire carrying model guns. His expertise includes surveillance and espionage devices, which he deploys during investigations.

Within the team, he applies specialized reconnaissance and information-gathering knowledge to operations. His role centers on technical support involving physical surveillance and equipment handling during cases.