Tru

Captain (or Lieutenant) Tru was a young officer that commanded the USS Vitality in the 24th century. He was a student of martial arts and always carried around a mek'leth. (Star Trek: Adventures)

Lieutenant or Captain

Starfleet paid little attention to the USS Vitality in the 24th century, as there was little need to. The ship's mission was to repair warp tears in space, so they appointed a mere Lieutenant as Captain of the ship.

Although technically, Tru was now ranked Captain, he was continued to be referred to as Lieutenant by higher-ups that had known him in the past. In a way, it was hard for other people to accept him as a Captain since his previous ranking and experiences were the latter.

Because his experience in the field ranked him as only a Lieutenant, in any other position outside his mission to repair tears, he was reinstated to his rank of Lieutenant.