Alien - In a Mirror, Darkly, Part II

Alien slave

In 2155, an alien slave was employed by Tholians aboard the Federation starship USS Defiant under the Gorn slave master Slar.

When that ship was stolen from a Tholian dock and commandeered by Jonathan Archer, an unknown reptilian creature attacked and killed Kelby, one of Archer's officers. The alien slave was interrogated in the Defiant's briefing room as to the identity of the murderer. Eventually, he revealed that the killer was his slave master, Slar. (ENT: "In a Mirror, Darkly")

His fate after being interrogated is unknown, though it is unlikely he would have fared any better under the Empire than he did under the Tholians.