The Specific origin of Kronak the Barbarian is not well documented. What is known, he was a barbarian despot who at some point usurped the crown on a subatomic world called Terragonia. Using a powerful artifact known as the "Ruby of Shadows" Kronak overthrew Terragonia's rightful King Modrian and enslaved it's people.
The plot involved the Hulk shrinking down to this subatomic world to become the champion of an old wizard Shamu-Shan who believes the Hulk was sent by the gods to fight Kronak and free it's people from this despots grasp.
The story was written by Len Wein with it's cover created by Rich Buckler and John Romita. Rich is credited as the primary cover artist, with John Romita involved. The issue's interior artwork was crafted by Sal Buscema's pencils and Joe Staton's inks.
Because of Kronak The Barbarian's obscurity with no specific information available about which ancient civilization(s) directly inspired the character, The Issue's portrayal of a most obvious Conan knock-off, it's blend of science fiction, fantasy, subatomic travel, and mystical characters, makes this comic IMHO a very cool Cosmic Barbarian oddity to have in my "Barbarians Among Us" collection.