The Sunburst Project was a military experiment involving a Metahuman strike force in NBC type conflicts. Low-level Alphas were chosen because of their physical toughness and general resistance to disease. Normal troops are severely hampered by the protective gear, but most Alphas can withstand the heat and burden for longer periods. Their actual powers or abilities weren't a consideration, the Army just wanted people who wouldn't fold in uncomfortable situations.
Severe mental and physical training combined with drugs and hypnosis were tried to heighten existing abilities. They were given many cutting edge treatments to boost their resistance to known or theorized chemical and biological agents.
Although the project was supposed to be rather tame, the commander used increasingly brutal and inhumane stimuli to "Toughen up his boys." The project would have been shut down, but someone within the command structure was running interference.
As the project continued the subjects grew increasingly unstable. During a grueling endurance test series in "Controlled" circumstances, an Alpha manifested and caused the test environment to run amok. The subjects were subjected to lethal amounts of heat, pressure , chemicals and other bizarre stimuli as they tried in vain to escape.
The results were gruesome. Most of the subjects died before they could be freed. The few that survived only did so because their powers protected them, but were horribly altered by the duress and conditioning. Its theorized that the hypno conditioning used to train them established mental templates that channeled their transformations in some way. For example, it was discovered that Armordillo associated his football mascot with Strength and Endurance during his evaluation. Under hypnosis he was commanded to picture that icon whenever he was under stress. Each subject was implanted with triggers that somehow reinforced existing mental pathways.
Everyone has 1d6 unluck, a little power defense and life support. Some have much more depending on their degree of mutation. Radium is more of an energy being, and gets all the post-human type powers. Night Terror rounded them up because they hate the government and should be fairly resistant to drug-based mind control.
Sunburst is the leader of the team. Physically, he is the least changed by the experience. He is filled with solar energy, constantly pulsing with light and heat. Mentally he is quite unstable, and after recovering he went on a rampage against the scientists responsible. As an alpha he could project bright light flashes, and could withstand high heat. He hates scientists and has led the team in strikes against MegaCorp and the military.
Maser was melted and fused into his NBC protective armor. What remains can pass for a costumed human, but his costume has become a form of skin. Mute and post-human, Maser is a living microwave laser, a coherent standing wave. Any damage to his skin causes energy to leak out, weakening him. Stoic before the change, he spends much of his downtime watching TV. He doesn't feel much contempt for normals - he doesn't feel much of anything. Given a choice he'd rather be at home with a beer, but he no longer has a home to return to and lacks a mouth. He suspects that it was his powers that scrambled the test equipment somehow, but doesn't discuss this (or much of anything else) with his team. This guilt keeps him with them as much if not more than their shared mutations. In battle he can be rather vindictive, going after anyone who has harmed him or his teamates with monomaniacal vigor.
Ray is no longer remotely human. When the Omega transformation overtook him, he mutated into something resembling a manta ray. He hates beauty, especially metahumans who look like fashion models and will target the enemy with the highest Com if possible. Ray lacks virtually any sort of empathy for normals and has written off his own humanity as a lost cause.
Armordillo was mutated into a large armored hulk of a man. He chose his name because of the segmented armor plates of his carapace make him resemble an armadillo, and because it was his schools football mascot. He wasn't too happy when he got mutated, but now accepts it and thinks its kinda cool being so strong and tough. If he wasn't mutated, he would be much happier living a more normal life but can no longer fit into society as a giant armadillo. He follows Sunburst because he's putting the hurt on bad people who deserve it, and really doesn't have anywhere else to go.