Magen

Magen was a female being, with narrow features and catlike eyes, who was trapped in Elysia within the Delta Triangle. Possessed of psionic abilities, Magen served as an adviser to Devna the Interpreter of Laws and Xerius the Speaker for the Elysian Council. When the USS Enterprise (NCC-1701) and the Klingon battle cruiser Klothos were also trapped in Elysia, Magen used her abilities to reveal a bomb hidden aboard the Federation ship before it had a chance to activate. 

Background
The was provided by Nichelle Nichols.

In the novelization Star Trek Log 4 by Alan Dean Foster, Magen is referred to as a native of Omega Cygni, and her powers are described as a sympathy shared by her people and intensified by their minds enabling them to see all that others do, concepts that are revisited in the Star Trek: Starfleet Corps of Engineers eBook Where Time Stands Still by Dayton Ward and Kevin Dilmore. There, however, her psionic powers are simply said to be a known ability that some of her people possess and she is easily recognized by the Starfleet crew as being Cygnian.

Magen