Halk Kar came from the planet Thoron, which is in the same solar system as Krypton. He visited the world of Krypton shortly before its destruction and met Kryptonian scientist Jor-L. Years later, Halk Kar eventually came to Earth, but when he arrived, he had no memory of who he truly was. Superman discovered him carrying a note written by Jor-L and theorized that Halk Kar may have been his brother.
Superman quickly realized that Halk Kar was less powerful than him and—instead of subjecting him to embarrassment over the fact that he may be weaker than his younger brother—opted to use his own powers to cover for Halk Kar's deficiencies. Unfortunately, this plan backfired on Superman, as Halk Kar began to assume a superior attitude to Superman and even begin to make romantic advances on Superman's girlfriend, Lois Lane.
Halk Kar and Superman joined forces to stop a criminal named "Wrecker" Ross, but during the incident, Halk Kar suffered an electric shock which restored his memory. He told Superman the truth about his origins and how he had once met his father Jor-L. Years ago, while on a pioneer voyage into space, he landed on Krypton with his damaged rocketship. There he met Jor, who explained that Krypton's destruction was imminent and repaired Halk Kar's rocketship, sending him away with the note which had a map from Krypton to Earth on it. Krypton exploded shortly afterward, causing Halk Kar to be put into suspended animation until he drifted to Earth to meet Superman, the grown-up son of Jor-L referred to in the note.
After explaining his story, Halk Kar bids farewell to Superman and returns to the planet Thoron in his repaired rocketship, leaving Superman with the experience of briefly having had a brother.
- This version of Halk Kar, including all history and corresponding appearances, was erased from existence following the collapse of the original Multiverse in the 1985–86 Crisis on Infinite Earths limited series. Even though versions of the character may have since appeared, this information does not apply to those versions.
- 2 Appearances of Halk Kar (Earth-Two)
- 1 Images featuring Halk Kar (Earth-Two)
- Quotations by or about Halk Kar (Earth-Two)
- Character Gallery: Halk Kar (Earth-Two)