Doctor Light is the name of several fictional characters in the DC Comics universe. The most prominent character named Doctor Light is a supervillain, a long-time enemy of the Teen Titans and Justice League who has lost many battles against them.
The first Doctor Light was a Golden Age supervillain who battled the original Doctor Mid-Nite. This character was fairly minor, and has not been seen since his three appearances in the Golden Age.
The first Silver Age Doctor Light was a supervillain named Dr. Arthur Light, who first appeared in Justice League of America #12. A retcon introduced in Secret Origins #37 revealed that this character was actually the third Dr. Light. His predecessor was his partner at STAR Labs, a scientist named Jacob Finlay. Finlay had used a technically advanced suit to control light as a minor superhero, but was accidentally killed by Arthur Light near the beginning of his heroic career. Light took the suit and the "Doctor Light" codename, using them for selfish, criminal means. He was periodically haunted by Finlay's ghost through the years, but could use the light generated by the suit to drive off this spirit.
Doctor Arthur Light was the minor but persistent foe of a number of heroes. He first fought the Justice League and, when he failed to defeat that group, he fought their sidekicks and former sidekicks, the Teen Titans. He then founded the Fearsome Five , but they were defeated by the Titans, and Light was violently expelled from the Five by his teammates. Each criminal caper led to Light's defeat, often humiliating him in the process. Light's most ignominous defeat was likely his defeat by Little Boy Blue and his Blue Boys - a group of non-superpowered children.
Driven by self-doubt and guilt, thanks in part to Finlay's ghostly presence, he volunteered for the Suicide Squad, a group of incarcerated supervillains who performed suicide missions for the US government in exchange for clemency. As a Squad member, he was less than successful in exonerating himself morally. On a mission against the patriotism-themed super-team called "Force of July", he killed Sparkler, the Force's youngest member, who was only a child. Finally, Dr. Light was convinced to attempt a heroic turn, and was consequently killed by Parademons on Apokolips. Light was thus sent to Hell, where he met Finlay's shade. Both men escaped and were returned to life, but Finlay soon died again and the hands of religious extremists. Dr. Light, freed of his ex-partner's hauntings, was briefly trapped in the Green Lantern's power battery, and as a consequence was temporarily transformed into living light. He later joined a short-lived incarnation of the Injustice Gang, in which he assisted Lex Luthor in building android duplicates of the JLA.
The controversial 2004 miniseries Identity Crisis revealed that Doctor Light had, at some point in the past, raped Sue Dibny, the wife of the superhero Elongated Man. As punishment, the Justice League brainwashed Light and induced amnesia in him, that he might forget that the attack had ever occurred. This mental block was apparently intended to explain Light's degeneration from a threat to the entire Justice League to a man who could be defeated by a schoolboy. He later recovered his memories, and after Sue Dibny was murdered, he hired Deathstroke the Terminator to protect him from the League. The forthcoming miniseries Villains United is to follow up on the Justice League's actions in this case and in related incidents.
Another Doctor Light debuted during the Crisis on Infinite Earths. Kimiyo Hoshi was a Japanese astronomer who gained the ability to generate and manipulate light upon her exposure to radiation released from a supernova. She became a superhero, and joined the Justice League and the Outsiders for a time.
Animated version
In the Teen Titans cartoon, Dr. Light is a fairly minor villain. Although a capable fighter, he lacks the brains to go with it. His powers which are derived from his suit include light energy blasts, and in the Season Four episode "Birthmark", a light whip capable of cutting through metal. In his first appearance, the Season One episode "Nevermore", he was winning until he got Raven angry, which unleashed her demonic side. He was nearly killed by her dark powers, and was mentally scarred. In "Birthmark", he was back at it and now with a light whip, but made the mistake of hitting an oil rig visible from the Titans Tower. After putting up a good fight, he declared "I'd like to go to jail now please" on sight of Raven.
