Before becoming a superhero, Dr. Raymond Keyes was a Professor of nuclear physics at Stanford University.
Unfortunately, his budget was cut and his access to the university's linear accelerator became limited, so he took a corporate job with Crey Industries in an effort to work unimpeded towards, as he called it, the greater good.
Unfortunately, he soon found out that his employers did not share his ideal. This realization came as he was developing a revolutionary battle suit that could harness and channel anti-matter into fierce attacks.
When he discovered that the company intended to use for the suits in a less then ethical way, he destroyed all records that would allow Crey Industries to create the battle suits en mass and took the prototype he had built with him when he resigned.
Dr. Keyes now found that he had a new purpose. He decided to use the high tech battle suit he designed to truly fight for the greater good.
The armor gave him the ability to achieve flight, super strength, and a whole host of other powers. The superhero Positron was born. While fighting crime in Paragon city, Dr. Keyes continues his research in nuclear physics until an unfortunate (or perhaps fortunate) accident changed his life.
While working in his lab, a random power surge resulted in a containment breach, exposing Dr. Keyes to toxic levels of radiation. Not only did he survive the accident however, he also found himself able to use his own body to generate and control anti-matter.
During the Rikti War, he used these powers to help defeat the enemy, but at a terrible cost. Due to serious injuries he sustained at that time, he found himself unable to control his powers as he once had.
With his extended knowledge of nuclear physics, Dr. Keyes understood very well the capabilities of his power, and their danger, especially uncontrolled. In an effort to protect others from being contaminated by radiation, he chose to remain imprisoned within his battle suit.
He constantly searched for a cure for his condition, all the while contributing to the defense of Paragon City and continuing to develop many technological breakthroughs for the good of all.
But the decision to seal himself within his suit took its toll on Positron.
Although it did allow him to contain the life threatening anti-matter, which left unchecked could level multiple city blocks, this decision eventually led him to become cold and distant, as people could only talk to the "suit" and not the "man".
He was always deemed to be the resident genius of the Freedom Phalanx, but being trapped in his suit made him feel more like a problem solving computer than a member of the team. This always irked him, to the point where he would go out of his way to show that he was a living, thinking, member of the team, often by creating the perfect gadget for a situation, or anticipating what the team would need before they asked for it.
As if to add to his turmoil, Lord Recluse's draining of the powers of all superheroes made Positron even more dangerous. His suit became heavily damaged, and began to leak anti-matter.
What Positron had feared had come to pass. He was placing the city he fought so hard to protect at risk. In order to keep the city safe from the radiation, Positron decided to seal himself in the Freedom Phalanx base until he was finally convinced to venture out to attempt to restore all superhero powers.
During the encounter with Prometheus, Positron inadvertently became the carrier of Prometheus's Fire. The power of the flames instantly repaired his armor, and boosted the effectiveness of his attacks. Positron was then able to return to Paragon City with the rest of the team, where he released the power of the flame and was thus able to return the powers of all superheroes.
During a later encounter, the Freedom Phalanx faced a corrupted incarnation of Hero 1 while investigating a rift created by the Rikti.
During the fight, Positron's armor was pierced, resulting in a nuclear explosion that killed many members of the team. Luckily, The Dark Watcher of Vanguard was able to resurrect the fallen heroes, restoring Positron's ability to control his powers in the process, finally freeing him from his self imposed prison.
Today, you will find Positron still fighting the good fight, using his knowledge and superpowers for the benefit of every citizen of Paragon City.