First DC AppearanceEdit
Justice League of America #12
First Story AppearanceEdit
Wings of the Eagles
In the show, as well as in the comics at first, Dr. Light's powers came entirely from his suit. Whether all his powers come from his suit in the Legendsverse has not been verified. Specific suit weapons seen included a thrown mine-like light bomb and perhaps focusers to form cutting light whips.
Either through his suit or via the ability of photokinesis, Dr. Light can, as his name suggest, control light. While he usually uses this to fire powerful energy blasts or set off blinding light charges, Light CAN use it at much higher degrees of sophistication, including forming force fields with it, bending the light around him to become invisible, and flight. By repulsing photons, Light can create areas of complete darkness, and suck the ambient light out of the area to increase his powers. He's also been seen utilizing the speed of light to briefly move at high velocities. In the comics, Dr. Light was originally a genius physicist, until certain events caused his brain to be greatly reduced in intelligence for a long time. Whether this is the case for the Legendsverse Dr. Light or he's just naturally not all that bright (Sorry! - LM) (Ugh, PUNS! *gets her mallet* -Z) is still uncertain.
One may be tempted to immediately call Dr. Light several rather mean things, and perhaps he even deserves them. But it wasn't always that way...
Though one must note that Dr. Arthur Light was never really a prize human being to begin with. He wasn't even the first Dr. Light: his partner Jacob Finlay at STAR Labs created the suit that allowed him to control light and attempted to use it to embark on a career as a hero, but before it could really begin Light accidentally killed him (supposedly), stole his suit and code name, and went to work for his own selfish, criminal means. In the comics Light was periodically haunted by the spirit of Finlay, though he could use the power of the suit to drive said ghost away, but this does not seem to have happened in the Legendsverse.
Dr. Light became a minor but persistent foe of the hero world: he started off fighting the Justice League and when he got nowhere with them he moved on to their sidekicks and young allies, the Teen Titans, who would become his greatest foes. He couldn't beat them either, despite his efforts (including, in the comics, founding the group known as the Fearsome Five, whose members also included the Troika: Gizmo, Jinx, and Mammoth); he would always lose and usually be humiliated in the process (He even lost to a minor group of Golden Age child heroes known as Little Boy Blue and the Boy Blues, who were not only children, but had no powers whatsoever). In the comics, Light's constant losses and Finlay's constant presence lead to him joining the government-sponsored villain team the Suicide Squad (where villains would take on suicide missions for amnesty for their crimes); this proved to only demonstrate his utter lack of character as on a mission the Squad battled the superhero team the Force of July (whose members included the possibly related to Billy Numerous' Silent Majority) and Dr. Light murdered Sparkler, the youngest member of the team. Sparkler was a mere child, and seeing him set off seizures of Dr. Light's constant failures in besting the Teen Titans, causing him to lash out, but that was still no excuse. Finally, (still in the comics), Dr. Light's life would become even MORE chaotic: Finlay's ghost managed to convince Light to attempt a heroic turn, but Light was about as successful as being a hero as he was a villain, except more so, as he was consequently killed. Light was thus sent to Hell, where he was physically reunited with Finlay. Both men were released from Hell (why is unknown) and returned to life, only to soon die again: Arthur Light suffocated while still inside his grave, while the desiccated Finlay clawed his way out of his own grave but was killed by a family of religious vigilantes (owtch). Arthur Light was again returned to life (the whys again unknown), and barely survived a great fall that his demonic tormentors may have intended to be fatal.
Dr. Light, freed of his ex-partner's hauntings, attempted to rejoin the Suicide Squad, but his appeal was summarily rejected by Amanda Waller, who lead the squad. He then went through a series of events which ended with him 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 holographic duplicates of the JLA. But that version failed as well, and all this additional comic information (which may not have even happened to show or Legendverse Light) did was prove that for all his power, Light was a loser.
Until Identity Crisis.
The 2004 miniseries answered, very brutally, why a villain with as much power and brains as Light went from battling the Justice League to being the punching bag of the Teen Titans and everyone else: Dr. Light had, in the past, actually succeeded in infiltrating the Justice League headquarters and brutally attacking Sue Dibny, the wife of then-member Elongated Man. While he was caught, his actions so infuriated the members of the League (exacerbated by Light threatening to do the same to every loved one of every superhero he could find) that they chose to, through their magician Zatanna, not only erase Light's memory of his deeds but literally lobotomize him to make him less of a threat. This was done, which resulted in Light going from dangerous to doofus (and having far reaching consequences later). Unfortunately, eventually the lobotomy wore off and Light regained his memory and former competence, making him far far more dangerous then before.
However, it has yet to be shown if the show or Legendsverse Dr. Light followed these exact events (while the story Crisis Point, as well as the fan story Via Negativa do through their events suggest that the events of the comics have been followed, neither are in the official 'fanon-canon'), or if Light's life in it is much simpler and he is simply dumb by nature. Whichever is true, Light has had no luck in the show against the Titans: his first battle with them went well until Raven unleashed her demonic side and nearly drove Light into a catatonic state (Nevermore), a factor that caused him to surrender the second he saw Raven in the Titan's second battle with him (Birthmark). His attempt to use Kole to increase his powers failed as well (Kole), and while he was lucky enough not to be in the final battle between the Titans and the Brotherhood of Evil (and hence possibly escaping other consequences, see explanation here), he was unlucky enough to try and rob a bank immediately afterward and run into every single Titan united against him (Titans Together): while that battle was unseen we will assume he lost again, quite possibly setting a speed record in the process. And in the Legendsverse, outside of joke appearances, Dr. Light's sole appearance only resulted in him becoming another victim of the Zap Pack.
Then again, if Dr. Light's comic history is any indication, the Titans should be cautious: when Light regained his competence he went from being a joke to a monster, capable of besting dozens of heroes on his own. So be careful with any signs you may make with a thumb and forefinger. He might just burn them right off.