Dr. Thomas Light is a very skilled man in the field of Advanced Robotics. He is also the "father" of Rock, Roll, Blues, and the first 8 Robot Masters (alongside 8 other Robot Masters who turns evil later. Two of those Robot Masters include Splash Woman and Concrete Man). In the past, he worked alongside Dr. Wily to make robots, but Light always got the credit for projects they did together. In the end, Wily took six Robot Masters, Ice Man, Guts Man, Bomb Man, Fire Man, Cut Man, and Elec Man, reprogrammed them, and set them off the destroy to city. In response, Light upgraded Rock from a common helper robot to the super fighting robot, Mega Man, and has been assisting his son by giving advice and upgrades ever since.
Much of Light's early life is unknown, but it's known that he and Wily went to Robert University of Technology to study Advanced Robotics. Together, they made many advancements that are seen now. During that time, they began working together, but Light got most, if not, all of the credit for the work they did together. Some time later, they were later nominated for the Nobel Prize in Physics, but Light won the prize. Eventually, Light met Dr. Mikhail Sergeyevich Cossack when he came over from Russia to do his thesis work and the two began friends. He also met Dr. Noele LaLinde and they developed a mutual romantic interest in each other.
First Robot Master
Light needed some money to start up Light Labs to fund his robot research, so he made a deal with the military. He would make robots for them, and they'll fund his research. After an unknown amount of time, he and Wily created DLN-000, dubbed Blues, the first Robot Master, and the first robot to have emotions, a personality, and independent thinking (but still bound by programming). Before Blues was shown to the military, Light took him around the city to show him the world, even getting him his trademark sunglasses and yellow scarf and at the end of the day, he heard Blues whistling a song that he made up. During the military exercise, Blues suffered a malfunction as a result of his unstable nuclear core. Nonetheless, the military continued to fund Light.
Later, Light was arguing with Wily about changing his core. Some time after that, he contacted LaLinde to relay his problems about Blues to her, while offhandedly joking that he wishes to remove his rebellious streak, which Blues (who was overhearing) took literally and ran off, feeling betrayed. Despite Light's best efforts, he was unable to find his first son and was forced to give up. Some time after that, he and Wily went their separate ways and Light no longer had to rely on the military and built robots for the betterment of mankind. He first built two "children", DLN-001 and DLN-002, named Rock and Roll respectively, due to his love of music. He would later build DLN-003 to DLN-008, called Cut Man, Guts Man, Ice Man, Bomb Man, Fire Man, and Elec Man (in the order) and unveiled them at Titanium Park to introduce the world to the Robot Masters.
Wily's First Attack
Later that day, while Light, Rock, and Roll were sleeping, Wily broke into Light Labs, reprogrammed the Robot Masters, and left to set them loose. The following day, Light and his children were horrified at the amount of destruction the Robot Masters were causing; and Rock volunteered to stand up to Wily, much to Light's initial dismay. In the end, he agreed and he and Roll worked to upgrade Rock Light from a normal robot who helps out around the lab, to Mega Man, the super fighting robot to fight against Wily. Equipping Rock with a special Mega Buster and a Copy Chip to Copy the Robot Masters' abilities. With the Mega Buster, Rock thus dubbed himself Mega Man and Light teleported him to the first Robot Master, Bomb Man.
Following the defeat of Bomb Man and Guts Man, Mega Man was depressed that he was destroying his fellow robots, but Roll brough him back around and reassured him that Mega Man was doing the right thing. And after the defeat of Cut Man, Elec Man, Ice Man, and Fire Man, he transported Mega Man back to Light Labs, noticing that his son was beginning to go mad with power and put him in an unbreakable block and watched quietly as he tried every weapon he copied from the Robot Masters to break free, which caused Roll to run away with tears in her eyes. This broke Mega Man out of his power madness and requested Light to take his powers away and claimed that he was turning evil. But Light reassured him that he wasn't evil and gave his son a rousing speech about building Rock in his image and giving him everything he has, except for "the burning in [his] heart". He agreed with taking away the copied powers, but only after Wily is defeated and gave him the Magnet Beam, which he assures Rock is a completely non-violent weapon and sends him to the outskirts of Wily's Fortress. Due to interference, Mega Man was unable to contact Light and Roll for the remainder of the attack. After Wily was defeated, Light was informed that the Robot Masters have broken free of Wily's programming and are ready to be returned to normal when they get back.
Time and Oil Blend Together to Make Trouble
Following Wily's arrest, Light had Mega Man, Roll, and the Robot Masters fix all the damage done to the city, free of charge to make up for his very Robot Masters causing the destruction and was confronted by Gilbert D. Stern and his partner, Roslyn Krantz, the former believes that Light is hiding something. Light and Rock later take part in Wily's prison-transfer to make sure Wily doesn't escape, but the convoy is attacked by a lone Sniper Joe. While Mega Man was dealing with the robot, Wily somehow escaped with nobody seeing him. Naturally, Gilbert believes that it was all planned and that Light and Mega Man were working with Wily and helped him escape. Light, to prove his innocence and give Mega Man a chance to find and capture Wily, allows himself to be arrested and tells Mega Man to go to his check on his sister.
After a failed attempt to find Roll, Mega Man (and Roslyn) contact Gilbert so they could talk to Light (he was being kept at Gilbert and Roslyn's office in the meantime). Naturally, Light was worried about his "daughter", and is horrified to learn that she was kidnapped, with traces of oil at the door to Light Labs alongside the groceries Light wanted Roll to pick up. Light was able to piece together that it was most likely Roll's kidnapping and Wily's escape were done by two experimental robots he and Wily started working on, but were unable to finish before the Robot Masters were unveiled: Oil Man and Time Man. One made for oil-spill management and the other able to manipulate time. He also mentioned that they were last tested at an abandoned workshop and that Wily is most likely hiding there and gives Mega Man and Roslyn the address.
In the end, Wily was long gone, but Oil Man and Time Man were captured and set to be reprogrammed for good by the recently released Dr. Thomas Light. While reprogramming Oil Man and Time Man, Light acknowledges that Wily will most likely return and that he'll need some help supporting Mega Man and considers building more helper robots, but reassures Rock and Roll that they'll never be made obsolete, as they are his children and no one is as precious to him as they are.
Rock, Roll, Auto, and Dr. Light are celebrating Rock's final moments as Mega Man and are happy that he'll be returning to helping out around the lab, but the joy is short-lived when a new Robot Master named Quick Man threw Rock into a wall and pinned him with his Quick Boomerangs, tripped up Roll and pushed her into Light, knocking them both into a chair, and punched out Auto all within a matter of seconds. He then told the group that Wily is back and built Quick Man and his seven "brothers", placed him at various areas around the city, and will launch a great attack in a few hours, unless Mega Man and only Mega Man stopped them. If they called the authorities, the Robot Masters would begin their attack early. He told Mega Man that he'll wait for him at Titanium Park in one hour. After everyone recovered from the attack, Light uploaded the coordinates and teleported Mega Man to the area. Later, Mega Man was having trouble with the Robot Master stationed in the area, not Quick Man, but Wood Man. He advised Mega Man that Wood Man's structure is durable, but quite fragile, and could beat him with a point-blank charged shot from the Mega Buster. After defeating Wood Man and copying his Leaf Shield, Light noticed a spike in Mega Man's power and warns Mega Man to watch himself as he proceeded to the hydroelectric plant, where the next Robot Master, Bubble Man, is.
After Mega Man defeated Bubble Man with the Leaf Shield, Light warns him that the sulfuric acid (a very corrosive mineral acid, quite similar to actual acid, but works well in large amounts of water) levels were getting dangerously high. When he copies Bubble Man's Bubble Lead, Light informs him of another energy spike and believes it to be a virus. He urges his son to return to the lab to figure out where the next Robot Master is, take care of the energy spike problem, and repair all the damage he sustained, but Mega Man was attacked by Quick Man again. After a brief battle, Mega Man is still unable to get a hit on Quick Man, and the Blue Bomber was further damaged and teleported to a geothermal plant where Heat Man is. Light warns him that losing the plant would be dangerous, among other things, but his transmission is quite garbled. At the end, Mega Man is fighting Heat Man, but is having trouble and tries to ask Dr. Light for help, but is cut off from him from too much interference.
Back at the lab, Light, Roll, and Auto watched as Mega Man cooled down/defeated Heat Man with the Bubble Lead, was informed of where Crash Man is, and copied Heat Man's Atomic Fire. They were also quite upset the way Mega Man mercilessly excecuted the already beaten Heat Man with his Mega Buster aimed at his head; Mega Man's eyes even turned red and he had a sadistic smile on his face. Light leaves to work on an anti-virus for Mega Man and leaves Roll and Auto to assist Mega Man. After Mega Man defeated Crash Man (in truth, Crash Man, during his huge bout of rage, littered the entire room with his Crash Bombs, which went off. Mega Man survived by putting up the Leaf Shield), Roll said that Light wanted Mega Man to return home, but before he could give an answer, he noticed Crash Man was still functioning. He tells Mega Man that Air Man is stationed on the various platforms that monitor the weather over the city. He copies Crash Man's Crash Bombs, then lays a stream of Crash Bombs. He then detonates them when he gets far enough away from the room, thus destroying Crash Man. When Dr. Light returns, he demands Mega Man return to be repaired, recharged, and upgraded, but he refuses and continues on to defeat Air Man.
Following the battle with Air Man, Light noticed that Rock's energy cells are almost completely depleted and urges his son to return home. Mega Man refuses, saying that he'll just take the remaining energy cells from defeated enemies and takes Air Man's Air Shooter. Light transports Mega Man to the Industrial Processing Plant, where Metal Man is located. He warns Mega Man to stop being reckless, but is ignored, especially just as he reaches Metal Man's boss area. Mega Man defeated Metal Man being distracting him with the Crash Bomb, sneaking up behind him, copying his Metal Blades, and hitting him with it, but Rock was damaged even further. Finally putting his foot down, Light engaged the emergency teleport and informed Mega Man to sit tight. Finally had enough, Mega Man destroys the communication device in his helmet and blocked the teleport signal, so he'll be left alone to defeat the other two Robot Masters.
Light has by now figured out that this is all Wily's doing and wonders what the doctor has done to his son. He pieced together that Wily has created a Trojan Horse virus, making Mega Man act differently. While Light, Roll, and Auto couldn't contact Mega Man, they could still monitor him and see that he's in Flash Man's area. Auto is tasked with calling up some old "friends" while Light himself attempts to hack into Mega Man and install a "tracking program and an antivirus countermeasure".
Light's Lost Son
Following Flash Man's defeat (He was beaten while distracted by Rock's hair, as he has no hair of his own. While upset over his lack of hair, Quick Man of all robots hit him from behind with a Quick Boomerang), Rock's copy of Flash Man's Time Stopper, and Quick Man forcing Mega Man to drink an E-Tank (a valuable canister that completely refills Mega Man's health), Light watched as Mega Man chased after Quick Man and reached his boss area. By that time, the Anti-Virus program was uploaded by 70%. In the end, Mega Man overcame Quick Man's superior speed by stopping time with Flash Man's Time Stopper and hitting him with a fully charged Mega Buster shot (in the game, the Mega Buster can't be used alongside the Time Stopper. On top of that, Quick Man actually slowly loses health while time is stopped). And when he touches Quick Man and copies his Quick Boomerang, Rock is suddenly thrown back and teleported to the Wily Castle II and has become completely loyal to Dr. Wily.
Back at Light Labs, Light has lost the signal and comforts Roll, who's crying over losing her brother. Suddenly, Auto comes in with the "friends" he called; those friends being Elec Man, Bomb Man, Cut Man, Ice Man, Fire Man, Guts Man, Oil Man, and Time Man. All of them ready to return Mega Man the favor of saving them from Wily's control.
- Dr. Light's first name, Thomas, was possibly named after Thomas Edison, a person known for inventing the Incandescent light bulb, and other inventions.