The brilliant scientist behind duotronic computers, whose M-5 multitronic unit took over the Enterprise and killed hundreds of crew on other ships.
Richard Daystrom made his name early in life by developing the duotronic computer systems on which Starfleet came to rely. Years later, eager to repeat that success, he brings his M-5 multitronic computer aboard the Enterprise to demonstrate that it can run a starship with only a skeleton crew.
Daystrom had impressed his own mental patterns on M-5, and the machine inherited his insecurities along with his intellect. When M-5 attacks other starships and Daystrom proves unable to stop it, he suffers a breakdown and is taken away for care. The Daystrom Institute bears his name. He was played by William Marshall.