Rokk Krinn is a founding member of the Legion of Super-Heroes under the code-name Cosmic Boy. Rokk is a Braalian and like all of his native race has the superhuman ability to generate magnetic fields.
Though Rokk is a Braalian, he was not born on Braal; he was born on Earth before his family moved back to Braal. This is why he has more control over his magnetic abilities than other Braalians.
Rokk's parents were struggling for work on the impoverished world of Braal, so he left at the age of fifteen for Earth to find work to assist his family. On a spaceship trvelling to Earth helped save billionaire R.J. Brande from an assassination attempt along with Lightning Lad and Saturn Girl. Brande was impressed by the youth and offered them work founding a team of young super-heroes. Rokk accepted and became Cosmic Boy, the team's first leader.
During his first year worked as a leader dedicated and being a figurehead as a founding member and the first leader even when just another active member. After sometime, a romance blossomed between Lydda Jath alias Night Girl of the Legion of Substitute Heroes.
After time he raised enough funds to bring his family to Earth, but a firebomb went off in the neighbourhood where they lived. His whole family was injured and his mother later died. This led Rokk to almost kill this also encouraged his younger brother, Pol Krinn, to join the Legion Academy as Magnetic Kid. When he agreed with his fellow founders that they were getting old and it was time they resigned, Rokk was pushing for his brother to be elected to the team in his place.
After 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, the former "Chameleon Boy," 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.
- Braalian Physiology: Cosmic Boy is a Braalian who have the natural ability to lift and manipulate metal. Cosmic Boy can produce a number of effects.
- Magnetic Manipulation: He can manipulate, repel or attract metal objects of varying sizes. Naturally, the more metal there is in an object, the easier it is for him to affect it magnetically. His super-magnetism has only a slight effect on the metallic particles of smog. He is able to juggle smaller metal objects. Cosmic Boy has pulled large iron meteors and satellites down from space with minimal effort, as well. He can use his magnetic power on rocks that contain iron ore. He once exerted "every bit" of his power to draw thousands of iron chunks upward into space.
- Magnetic Force-Fields: Cosmic Boy can protect himself from physical harm, can stretch his fields to protect a large group, and can suspend persons or objects in the air.
- Magnetic Flight: Cosmic Boy can suspend himself in flight by riding the Earth's magnetic field.
- Electromagnetic Sight: By concentrating, Cosmic Boy can perceive the world around himself solely as patterns of magnetic and electrical energy. He can perceive the natural magnetic auras surrounding living beings, as well.
- Magnetic Pulse: Cosmic Boy can focus his magnetic energy into powerful concussive blasts. He can also overload or short-circuit electrical systems.
- Energy Absorption: Cosmic Boy has been shown absorbing some forms of energy through his magnetic force fields to temporarily boost his own strengths. Early in his career with the Legion, he absorbed Lightning Lads's lightning blast.
- Geomagnetic Link: Cosmic Boy is tied very closely to Earth's or what ever planet he is on EM Field. As is it effected, so is he. He knows instinctively all that happens to it.
- Leadership: Cosmic Boy is a charismatic and effective leader, as seen during his successful tenure as the Legion's first leader.
- Non-Magnetic Materials: Cosmic Boy's power cannot affect non-magnetic metals, such as aluminum and gold, or organic substances like wood.
- Distance Limitation: Distance affects the limit his magnetic control has over an object, as does the amount of metal in or on that object. For example, he once caught a falling worker who was only a couple of dozen feet away. But considering that Cosmic Boy had to catch the man by focusing his power on the small amount of metal in the man's tools and belt-buckle, "straining every fiber of his being" in the process, he thought the man was "pretty far" away.
- 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.
The events of the Infinite Crisis miniseries have apparently restored a close analogue of the Pre-Crisis on Infinite Earths Legion to continuity, as seen in "The Lightning Saga" story arc in Justice League of America and Justice Society of America, and in the "Superman and the Legion of Super-Heroes" story arc in Action Comics.
- Adventure Comics (Volume 1)
- Adventure Comics (Volume 2)
- Final Crisis: Legion of 3 Worlds
- Legion Lost (Volume 1)
- Legion Lost (Volume 2)
- Legion of Super-Heroes (Volume 1)
- Legion of Super-Heroes (Volume 2)
- Legion of Super-Heroes (Volume 3)
- Legion of Super-Heroes (Volume 4)
- Legion of Super-Heroes (Volume 5)
- Legion of Super-Heroes (Volume 6)
- Legion of Super-Heroes (Volume 7)
- Legion Worlds (Volume 1)
- Legionnaires (Volume 1)
- Superboy (Volume 1)
- Superboy and the Legion of Super-Heroes
- Supergirl and the Legion of Super-Heroes
- The Legion (Volume 1)
- 445 Appearances of Rokk Krinn (Pre-Zero Hour)
- 62 Images featuring Rokk Krinn (Pre-Zero Hour)
- 8 Quotations by or about Rokk Krinn (Pre-Zero Hour)
- Character Gallery: Rokk Krinn (Pre-Zero Hour)
- Cosmic Boy at dccomics.com
- Cosmic Boy at Wikipedia.org
- Rokk Krinn article at Memory Beta, the licensed Star Trek publication Wikia.
Legion of Super-Heroes member