Overseer was the leader of the Spyricans. When he detected the human astronauts on the way to his planet, he feared for the disruption of the Spyrican society. In an attempt to prevent thier arrival, he bombarded thier ship with cosmic rays, giving them great powers.
Believing that these now superhuman travelers would one day return to finish thier “invasion,” Overseer started experimenting with cosmic rays on his own people, creating The Unparalleled as champions to defeat the incoming threat of the “Four-Told.” The Spyricans who were mutated into monstrous forms, however, were banished, with Overseer using them as enemies to train the Unparalleled. This Monster Mob were demonized as outsiders, but secretly thier leader still served Overseer.
When the Fantastic Four finally arrived on Spyre, the Unparalleled managed to defeat them, but Mr. Fantastic quickly realized Overseer’s machinations and revealed them to the public, causing riots.
The Thing, upon realizing it was the fault of Overseer that he had lost his humanity, attacked Overseer, intending to kill him. Overseer used a suit of robotic battle armor to even the odds, but was overwhelmed and would have been killed if not for the intervention of the Invisible Woman.
The battle left Overseer near death, with the Spyricans holding the Fantastic Four responsible. Overseer challenged Mr. Fantastic to face his crimes, and Fantastic battled him on the street. However, Fantastic appealed to his better nature pointing out that his quest to master and control everything was destroying his world. The two reluctantly decided to cooperate, and Spyre began to heal as the Fantastic Four departed.