Starmen of Different Places and Another Time

Prince Gavyn was the younger son of the emperor of the intergalactic empire known as Throneworld. When his father died, his sister assumed control and as a custom for such manners, she executed him by leaving him float in space. However, as a mutant, Gavyn survived the airless vacuum of space and was retrieved by the elderly alien known as Mn'Torr. Granting the prince a pair of jeweled wrist bands that harnessed the power of the stars. As Starman, Gavyn protected the empire that spurned him and assumed the role of emperor when his sister died, while he married his true love.

David Knight was the oldest son of astronomer and millionaire Theodore Knight, aka the original Starman of Earth-Two. Although at first a reluctant hero, with his father giving his Cosmic Rod to fellow mystery man the Star-Spangled Kid instead of either of his sons, Ted would ultimately find within his son the heart of a champion. However, shortly after embarking on his costumed career, David was shot by the son of the elder Knight's arch-enemy, the Mist. However, a quirk in the fabric of time-space jettisoned David back decades.

Although in a Post-Crisis world, Davis was sent to forty years prior to the 1950's , where he would be that era's next Starman, in the pre-Crisis world of Earth-Two he was instead sent forty years prior to the 1980's in the early 1940's. Due to the confusion of his unexpected time travel experience, David became a misguided villain who sought out the ancient Atlantan book of Thoth, and was subsequently defeated by his father’s  Justice Society teammate, Doctor Fate.

In an alternate future, Prince Gavyn perished defending his Throneworld during the Crisis on Infinite Earths, after which his own genetic material was passed along to a resident of Earth. The recipient of his awesome power was hitchhiker Will Payton who would next adopt the mantle of Starman for a period of time before giving his life to save humanity from the evil Eclipso. Payton's counterpart in the same alternate future would have been Jack Knight, the younger son of the original Starman of Earth-Two who had himself had both the mantle and the powerful cosmic rod bestowed to him to protect his world following his brother's premature passing