Doctor Lax was a 23rd century Human man, a scientist who served aboard the Federation's Research Satellite-5 space station in the 2260s.
History
In 2266, Lax was head of the station's experimental time travel cabinet project.
Professor Andres and Dr. Njam asked Lax to help them hide a prototype N-cycle bomb in Earth's past to prevent its misuse as a metaweapon. Lax sent Andres and the bomb to southern California on 3 April 1955.
Njam then betrayed both men. Njam shot Lax in the back, blanked the time travel controls, then fled the station, leaving behind a random demand. Lax restored most of control settings before he died, chose enough that James T. Kirk was able to retrieve Andres and the bomb. (TOS comic: "A Bomb in Time")