Doctor Njam was a 23rd century Human man, a scientist who worked aboard the Federation's Research Satellite-5 space station in the 2260s.
History
In 2266, Njam was a member of the N-cycle bomb project under Professor Andres. Andres approached him with the idea of using an experimental time travel cabinet to hide their metaweapon prototype in Earth's past until the Federation swore never to use it. Njam said he'd help.
But after Doctor Lax operated the time machine and sent Andres into the past, Njam shot Lax in the back and betrayed Andres. He blanked the time travel controls and fled the station. He left behind a blackmail video tape demanding one billion credits within 24 hours to keep the bomb from going off.
Unknown to him, however, Lax restored most of the time settings before he died. While James T. Kirk and Montgomery Scott went back in time to track the bomb, Spock located Njam and tried to reason with him logically, but Njam said he didn't value life as much as Spock. (TOS comic: "A Bomb in Time")