Special Instructor working for NERV and Asuka's guardian before her arrival at Japan's branch of NERV.

She and Misato used to date in college. They later reconcile at a certain point in the stories/

Kaji appears to be a triple agent, working as a special inspector for NERV, while secretly investigating the organization for the Japanese Ministry of the Interior, and at times seemingly acting as a cat's-paw both for and against Gendo Ikari and SEELE. His motivation of doing this if to "find the truth"./