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Official Site: DC Comics

Cosmic Boy (Rokk Krinn) is a fictional character, a comic book superhero in the 30th and 31st centuries of the DC Comics universe. He first appeared in Adventure Comics #247 (April 1958). He is a founding member of the Legion of Super-Heroes, and was the original leader in all incarnations of the Legion. His character has been fairly consistent in past versions, with a serious attitude and a strong sense of duty, while the "Threeboot" version leans on the manipulative side.

He is a founding member of the Legion of Super-Heroes, along with Lightning Lad and Saturn Girl and he has the superhuman ability to generate magnetic field. Cosmic Boy's brother, Pol, eventually joined the Legion as Magnetic Kid, but died during the "Magic Wars". Cosmic Boy is one of the few Legionnaires ever to have his own miniseries, which ran for four issues in the mid-1980s as a spin-off of the Legends cross-over.

In the pre-Zero Hour Legion, Cosmic Boy was romantically involved with Night Girl (Lydda Jath) from the Legion of Substitute Heroes. During the "Five Year Gap" following the Magic Wars, he lost his powers in the course of a war between the planets of Braal and Imsk (the homeworld of Shrinking Violet), in which the Imskian army used a "dampener" on the magnetic fields within the Braalian soldiers. "Vi" was on the scene when her fellow Legionnaire was crippled by the dampener during the battle of Venado Bay, and harbored deep guilt for years. Now going by plain old "Rokk Krinn", Rokk retired to the slums of a demilitarized Braal with his wife Lydda, who gave birth to their son "Pol" (named for Rokk's brother). When Reep Daggle reformed the Legion, a powerless Rokk joined up, moving his family to the Legion's new headquarters. The former "Cosmic Boy" continued to serve with honor during the adult Legion's tour of duty, proving that he needed no powers to be a hero. Rokk did however regain his powers shortly before Zero Hour, thanks to a special pair of power gauntlets. He took on the codename "Polestar", only to renounce the power gauntlets after they began to affect his mind. After learning that he was apparently destined to become the Time Trapper, Rokk and the rest of the Legion were erased from history by Zero Hour.

In the post-Zero Hour Legion, Rokk Krinn came from a poor family but became a superstar in the Braallian sport of Magnoball, earning the nickname "Cosmic Boy" after winning the Magnoball Cosmic Games. He sent most of his earnings to his family, unaware that his manager, Alex Cuspin, was embezzling them instead. After being approached by R.J. Brande to form the Legion, Saturn Girl discovered and revealed the truth about Cuspin. Rokk promptly dismissed his manager and had him arrested. The founding members voted him leader, but soon after found out that Leviathan, a Science Police veteran, had been appointed to leadership by the United Planets President. Leviathan would shortly thereafter give Cosmic Boy the leadership position after the death of Kid Quantum, a position he served in very admirably. After the attack on Earth by the White Triangle Daxam, he seemed to turn into a controlling martinet under the thumb of UP President Chu. During this period, he made many unpopular decisions, including forcing his best friend Garth Ranzz and Ultra Boy off the team. However, this was a ruse planned by himself and Invisible Kid to expose the corruption of the UP President.

Cosmic Boy has not been a contender in any CBUB matches.