Cosmic Boy is one of the three
founding members of the
Legion of Super-heroes, along with
Lightning Lad and
Saturn Girl.
Rokk Krinn is Cosmic Boy's real name. He is from the planet Braal. Braal is home to animals composed of living metal, who attacked the humans
who settled on the planet. To combat this problem, the people of Braal evolved the power of magnetism, allowing them to repel and attract the animals.
Cosmic Boy is romantically involved with Night Girl, a member of the Legion of Substitute Heroes.