Dr. Emmett Vale (voiced by John Rubinow) was a minor character in Superman: The Animated Series. Appearing in the Season 1 episode "The Way of All Flesh", he was a physician at Stryker's Prison who was secretly on Lex Luthor's payroll.
On Luthor's orders, Dr. Vale infected the mercenary John Corben with the rare Orozco's retrovirus by putting it in Corben's food. This was all part of an elaborate plot by Luthor to gain Corben as an ally in his quest to destroy Superman. Corben was unaware of how he became infected, but Vale and Luthor together staged a breakout from Stryker's in which Corben escaped. After the breakout, Corben would undergo the procedure that turned him into the cyborg Metallo while Dr. Vale was paid handsomely enough to retire from his position.
Dr. Vale did not live long enough to enjoy his reward, however. Considering the doctor a loose end, Luthor had Vale eliminated. Vale's death wasn't shown, but when Superman confronted Luthor about finding Vale, Luthor responded by saying there wasn't anything left of him to find.