The human chief of staff to Ambassador Sarek, who in the episode Sarek helps to hide the ambassador's Bendii Syndrome so that a final treaty with the Legarans can be completed.
Ki Mendrossen is a human diplomat who heads the personal staff of the Vulcan ambassador Sarek. He appears in the third-season episode Sarek, set in 2366, when the party comes aboard the Enterprise for a conference with the Legarans that will crown Sarek's career.
Mendrossen is protective to the point of obstruction, keeping Picard at a distance and insisting the ambassador must rest. As outbursts of anger spread through the crew, it emerges that Sarek has Bendii Syndrome, that his control is failing, and that the young Vulcan Sakkath has been using his own mind to steady him.
Faced with the evidence, Mendrossen admits that he has helped conceal the illness out of loyalty and belief in the mission.