Mexin was the overlord of the Farrian.
Mexin led an invasion of the planet Ballustra through a CVE. He was keen for others not to think of the Farrian as savages. Mexin shot Adric in the leg after Romana II continued to insult him.
He was ordered to withdraw after the Fourth Doctor destroyed the CVE generator; he complied. His ship was damaged by the CVE and it was unlikely he survived. (AUDIO: The Invasion of E-Space)