Garth

Garth, formerly a Starfleet Fleet Captain, was the Crowned King of the Universe until a well known cheater cheated him out of his Empire by tricking him into taking a pill that made him forget he was a King. He also created the most powerful explosive which he used in his conquest of the Universe. (TOS: "Dagger of the Mind II: The Wrarth of Garth").
He was a self proclaimed Darth which was a term unknown to many. Some of his other titles include: Dark Lord of Axxanar, Dread Lord, God Emperor, Emperor of the Known Universe, Magistrate of the Golden Dawn, and Manny's Automobile Repair Clerk.
His exploits are required reading for all cadets at Space Academy.
He was the personal hero and role model for Queen of the Universe Kathryn Janeway.