Senni Vek was a male green-skinned Twi'lek bounty hunter who worked for GenoHaradan Overseer Ithorak Guldar in Ahto City on Manaan during the Jedi Civil War. In 3956 BBY, he was often complaining about his abusive boss, and occasionally wore the uniform of a Sith officer to make himself look intimidating, though he favored the Echani light armor when on assignment.
Though the Overseers were not supposed to be aware of each other's identities, Vek was an acquaintance of another Overseer, the Rodian Hulas. Given his disgruntled relationship with Guldar, Vek was easily convinced to do a special assignment for Hulas; to track down feared bounty hunter Calo Nord and provide him with an invitation to join the GenoHaradan. To Vek's surprise, however, Nord fell in battle with the former Sith Lord Revan. Vek improvised and extended Hulas's offer to Revan, though he doubted the redeemed Sith would accept the offer.
In the light side version of the events, it is assumed the Revan did not agree to join the GenoHaradan, and Vek is never seen again.
After accepting Hulas's offer to join the GenoHaradan, Revan encountered Vek again in the Manaan swoop lounge, during a mission to kill Guldar. Revan can persuade Vek to help him kill Guldar, or he can kill them both.
Revan can also persuade Senni Vek to leave his master (in front of the hangar bay), before confronting Guldar inside, with enough Force Points in persuade. If Senni Vek leaves Guldar, Revan only has to kill Guldar and the droid is left outside the hangar - harmless.