Marcus, Dr. David
(Played by Merritt Butrick)
Along with his mother, Dr. Carol Marcus, a key scientist on Project Genesis in 2270-80s, and the only son of her and James T. Kirk. David introduced unstable protomatter in the project's matrix as a shortcut, an unethical move, and the resulting terraformed body, the Genesis Planet, proved unstable. Marcus was murdered by Klingons in 2285 after being taken hostage during their raid for the Genesis data.