Dr. Kinji Obatu was the Ugandan finance minister, but when the Grandmaster created the Squadron Sinister, he presented Dr. Kinji Obatu with a Power Prism (which was in fact a Skrull named Krimonn) to turn him into the counterpart of the Squadron Supreme's Dr. Spectrum.
Battling the Avengers
Obatu was a member of the first Squadron Sinister they were sent to fight against the Avengers in a competition between the Grandmaster and Kang the Conqueror.
Battling Iron Man
Dr. Spectrum reappeared, attacking a Stark construction site in Detroit while Tony Stark was working there. Iron Man battled him, but the fight was inconclusive and Spectrum escaped. Spectrum attacked him again while he was being congratulated by the mayor of Detroit. After Iron Man's ultraviolet light proved superior to Spectrum's Power Prism, Spectrum fled once more. Obatu then approached Stark in his civilian identity and asked to hire Iron Man as his bodyguard when the entity Rokk appeared, threatening Obatu's life. Rokk kidnaped Obatu and went after Roxanne Gilbert, having telepathically sensed a connection between her and Stark. Tony (as Iron Man) pursued Rokk to Roxanne's organic food store. Just as Rokk was nearing defeat he vanished; Dr. Spectrum appeared and revealed that he created Rokk with the Power Prism to wear him down.
Still, Iron man managed to escape. As Spectrum searched for his foe he found Iron Man near Roxanne and attacked. Iron Man was swiftly beaten and the Power Prism decided to make Iron Man the new host for its power.
Thor battled the possessed Iron Man and summoned a rainstorm that shorted out exposed parts of his armor, defeating him. With the power gone from Iron Man, Dr. Spectrum reclaimed the Power Prism and battled Thor, but another Iron Man arrived on the scene to aid his fellow Avenger. The new Iron Man beat Dr. Spectrum, smashed the Power Prism and unmasked him as Dr. Obatu.
Obatu was deported back to Uganda where he stood trial for crimes he had committed. Sentenced to death, he fled from the firing squad and allied himself with a witch-doctor. He and the witch-doctor wound up fighting the Black Panther, Brother Voodoo and the Thing. During the battle, Obatu fell over a balcony to his death.
Billy Roberts was an evangelist who elicited unwavering devotion from his religious flock. One of his followers, sanitation worker Bob Farmer, found the discarded power prism left behind by the former Doctor Spectrum, Kinji Obatu after his confrontation with Iron Man. Using the prism to expand his power base, Roberts as the new Doctor sought out the other members of the Squadron Sinister. Along with Hyperion, the Whizzer and Nighthawk, the quartet were themselves recruited by the alien Nebulon leading to a battle with the Defenders. While Nighthawk switched sides, his three former comrades continued their criminal careers upon returning to Earth following their last defeat, although once more it was the Defenders who vanquished the terrible trio. On one later occasion, when the power prism was in the possession of the Avenger known as the Wasp, her allies sought out Roberts who had been made to forget his former felonious ways. Seeking to reclaim the prism under the guise of aiding the Avengers, he was nonetheless vanquished once more soon after reclaiming it.
Power Prism would eventually leave him and temporarily stay with a factory work and career criminal named Martha Gomes before choosing Alice Nugent as its next host.
Alice Nugent was a former lab assistant of Henry Pym. Prior to Alice becoming Doctor Spectrum, her Power Prism belonged to Martha Gomes, who was a career criminal and had been controlled by the Purple Man for most of her criminal life. She received her Power Prism from Martha Gomes. As an agent of the Grandmaster's Squadron Sinister, Alice wanted to takeover the world in order to make it a better place
When Alice Nugent originally worked for Hank Pym he had no clue she owned the company that was employing both of them. She had wanted to learn Pym's research methods. Alice Nugent founded Nugent Technologies which had earned a good reputation as leaders in the telecommunications field.
Doctor Spectrum is an alien superhero from a distant world where they where team of heroes similar to the Avengers called the Squadron Supreme. The people of their world feared their power and turned against them. As a final solution Hyperion destroys his home planet along with his team on it, escaping into space in his Citadel.