Dr Ritsuko Akagi is NERV's Chief Engineering Officer and the one responsible for the care and maintenance of the EVA units, she is also the one that designed the entire system responsible for hooking up the pilots to their units; a genius in applied mathematics, she is the one With the responsibility of keeping the units in top condition for battle. A former classmate of Misato, it is believed that she had an affair with Misato's boyfriend, Kaji; this has left an indelible mark on Misato, which blames Kaji, not Ritsuko for their breakup.