Jor-El and Lara El
Jonathan and Martha Kent
Lana Lang (High School sweetheart), Lois Lane
When a mounting chain reaction threatened to destroy the distant planet Krypton, Jor-El tried to warn the planet's highest councilmen. However, due to their blind and misplaced faith in the A.I. monitor Brainiac, the Council disregarded Jor-El's warnings. As soon as he realized it is too late, Jor-El and his wife, Lara El, with great sorrow embarked their beloved son Kal-El in a ship set to take him to a distant planet.
When he arrived at Earth, more precisely, in Smallville, Kansas, Kal-El was found by Martha and Jonathan Kent. They decided to take the marooned child home as if he were their own born son. Kal-El grew up as Clark Kent and during his teen years, he soon came to see that he was not as other adolescents. Realizing that time had come, Martha and Jonathan decided to tell Clark the truth and showed him the space ship in which he was found as a baby. Inside, there also was a strange device that Ma and Pa could not figure out. The apparatus was activated by Clark's DNA alone and it contained a recorded message from his birth parents. They told him why they were compelled to send their son off to another planet. They also explained why they had chosen Earth in particular: unlike Krypton that has a red sun, Earth's yellow sun contains properties that would grant Clark certain abilities while he was growing up. Jor-El and Lara knew this way he would be protected from any harm. Finally, they warned to him that because of this, some people might want to destroy him, but despite of that, he should never use his powers in anger. Clark didn't take this information too well, but eventually he came to terms with whom he is.
After graduation, Clark moved to Metropolis and got a job as a journalist for the Daily Planet, so that he could hear about disasters as they occured and then save the day. There he met Lois Lane, a lively journalist who inadvertently coined his alter ego name... 'Superman'. Superman decided to give Lois an interview so that the world learned of his story and benevolent intentions. Due to Lois's knack for getting herself into danger and subsequent rescues by Superman, the two develop a close bond and eventually fall in love for each other.
During a demonstration of a new weapon system held by businessman Lex Luthor, Clark was seen in public as Superman for the first time, as he tried to foil an attempt to steal Luthor's LEXO Suit. Despite failing, Clark soon unveiled a plot that involved a deal between Luthor and the Kasnian terrorists to arrange his weapon to be stolen in exchange for a million dollars. When confronted by Superman, Luthor showed his true colors and tried to lure Superman into working for him. Superman attentively listened to Luthor's babbling, to which he simply replied with a menacing "I'll be watching you, Luthor".
Superman faced many enemies, but few were as devious and dangerous as Lex Luthor. He tried over and over to control Superman, resorting to all sorts of schemes and plots. However, if there is someone worse than Luthor, that would be Darkseid, the tyrannical ruler of Apokolips. Darkseid was fixated on taking over Earth; and for that he needed to go through Superman. So, he resorted to the most unspeakable actions to meet his goals, causing a great deal of pain and suffering for Superman in the process.
Powers & Abilities:
Superman's powers include flight, super strength, near invulnerability, telescopic, x-ray and heat vision, acute hearing and precise muscle control that allows him to impersonate anyone's voice.
Superman is vulnerable essentially to three things: red sunlight, kryptonite, and magic. The red sunlight negates the effect given by Earth yellow sun, which means that Superman becomes as vulnerable as any other human being. Kryptonite is a radioactive piece of rock from the exploding planet of Krypton. Just a tiny piece of kryptonite is enough to make Superman ill, and a larger quantity renders him so weak that a prolonged exposure can effectively kill him. Finally, Superman has no defense against magic, so he's as susceptible to mystic forces as a normal human being.
For further character development, refer to Superman's bio in the Justice League Unlimited's character guide.