Kensuke Aida is an otaku, a military buff, Toji's best friend, and one of the "Other Children," Eva pilot candidates in the same class as Shinji, Toji, Rei, Asuka, and Hikari. His hobbies include camping in the mountains surrounding Tokyo-3 and playing at simulated war reenacting - by himself. Kensuke solidifies his friendship with Shinji after Shinji saves him and Toji during the fight against the fourth Angel, Shamshel. Kensuke dreams of becoming an Eva pilot and ceaselessly begs Shinji to pull strings in NERV so he can be selected as a pilot, despite Shinji telling him that he has no say in the matter. He also seems oblivious to the intense physical and psychological duress endured by Eva pilots. Nevertheless, Kensuke enjoys the privileges of being the friend of an Eva pilot; he and Toji accompany Shinji on the excursion to the UN combined naval fleet during the transportation of Unit 02. Like presumably every one of Shinji's classmates, Kensuke's mother is deceased. Like Toji, Kensuke has a crush on Misato Katsuragi. He is rarely seen without his camcorder at hand.
Kensuke is named after a main character in the novel The Fascism of Love and Fantasies (Ai to Gensou no Fascism) by Ryu Murakami. He is also similar in appearance to the character Jean, from Hideaki Anno's earlier anime Nadia: The Secret of Blue Water.