Kid Miracleman/Marvelman for those unaware:
Incredible strength (able to lift hundreds of tons), superhuman speed and able to fly at around Mach 3. Invulnerable and able to survive in space without ill effect. Exceptionally intelligent beyond the human norm. Able to cause thunderclaps by clapping his hands.
He could also influence people's minds and fire beams of energy (heat most likely) out his eyes.
History: Johnny Bates, like his fellows Richard Dauntless and Mickey Moran, was chosen by the government to be used as a guinea pig in experiments employing alien technology salvaged from a crashed spaceship. The criterion for picking him was that he was an orphan, who would thus not be missed - as with his fellow victims his parents had been R.A.F. personnel killed during the War. The scientist Gargunza used the alien equipment to grow a mindless superhuman clone of Micky, and then dropped that clone into hyperspace. Then he implanted a device in the child's brain that could be triggered by a code-phrase (in his case "Kimota"), allowing the human child to swap places with the superhuman adult. Qualms about the controllability of these new beings stopped them being used in the field however; instead they were placed first in a sophisticated form of virtual reality, allowing them to live out bizarre adventures that checked their response to different situations (see the original version of this character - these were his adventures). Finally the government deemed their new creations too dangerous, and ordered their destruction.
The trio were awakened for the first time, and sent on a mission to stop an alien invader over the Atlantic. This invader was in fact a fake, being a flying facade concealing a nuclear device. When the trio were close enough, it was detonated. Kid Marvelman had sensed something was wrong just in time, and flew away at supersonic speed, avoiding the blast. His two cohorts were not so lucky - Young Marvelman was killed, and Marvelman was forced into human form and rendered amnesiac.
Perhaps understandably, considering the attempt on his life, Johnny decided to never change back to his little boy self. He grew up in his superhuman form, and realised that as the only person with such power, he could indulge his every whim. He become president of SunBurst electronics, a multimillionaire. Then, decades after thinking he had become the only superhuman on the planet, he heard that Marvelman had returned. It wasn't difficult to track down his old friend, since he knew his secret identity, and he invited Mike and his wife Liz to meet him. However Johnny Bates had no desire to share the world with another like him, and he fought his former firend across London. With much more experience of how his powers worked, he soon gained the upper hand...until in his moment of victory, his gloating proved his undoing. For the first time in years he said his mentor's name "Marvelman" and transformed back into 14 year old Johnny.
Johnny was in shock, still the boy he had once been, but remembering all the evil his other self had done. He was sent to a remand centre, where he was tormented by the other inmates. Inside his head, his superpowered self railed to be let loose, but Johnny kept him caged, until the day when a group of classmates decided to anally rape him. Saying Marvelman again, he transformed. He killed his attackers, and anyone else he encountered, transforming London into a charnel house before Marvelman and his allies caught up with him. Finding him virtually invincible, the Warpsmiths teleported a brick into his brain and girder into his chest. Even this wasn't enough to kill him, but the pain was sufficient to convince him to change back to Johnny. The tearful child cried to his friend Mike about everything that had happened, and Marvelman showed mercy and killed him.