Ki Mendrossen served as Ambassador Sarek's chief of staff when the ambassador visited the USS Enterprise-D in 2366. He was very protective of Sarek, and declined to allow Picard to give Sarek a tour of the ship, explaining that Sarek's advanced age made him easily tired. Mendrossen was trying to hide that Sarek was suffering from symptoms that were later shown to be the result of Bendii Syndrome, a rare disorder which causes loss of emotional control in Vulcans over 200. (TNG: "Sarek")