Cadmar was an Aquan male, native to the planet Argo. He was one of three Senior Tribunes who sat on the Ruling Tribunal of the Aquans. His role was, in part, to interpret the Aquan ordainments.
In 2269, a chance encounter with the James T. Kirk and Spock from the USS Enterprise, who were believed to air-breathers from Argo's surface.
Following a resolution, Cadmar and the Tribunal declared it would pass new laws, asserting the need for a continuation of contact with the surface Aquans. (TAS: "The Ambergris Element")