thumb|left|upright=1|Doc Hamilton

Robert Hamilton is a trainee of U.N.T.I.L. and a medical expert in the research department. Born and raised in Millennium City, Hamilton has an older brother and father who he is very disconnected from. At a younger age his mother passed away from an illness that the doctors could not explain. With her passing, Hamilton wanted to make a difference and decided to enter in the world of medicine. With him not having super human abilities, Doc is one of the most compassionate and caring persons to know. He also is a trained agent who uses gadgets and weaponry to out maneuver his opponents.

Doc Hamilton - Origins

David was always aware that his strength was beyond normal humans but he never knew how much stronger he actually was. The only one who knew of David's true abilities was his best friend Nate.

Not long after David's superhuman potential was clear, a powerful robot attack his hometown, clearly focused on killing David. David was pushed to his limits as the fight destroyed most of downtown. The fight ended as David, seemingly flying for the first time, smashed the robot into a nearby building. Using all his strength, David punched right through the robots head, destroying it and bringing down the building with the force of his punch. Minutes went by, as the dust began to settle, before David dug his way out through the rubble. Shocked, dazed, and confused, David just left.

After watching everything on the news about the invasion of Michigan, David realized his purpose. David realized then that it's not about having power, anyone can aquire power. It's about having the power to do whatever you want and choosing to do good. David knew, for the first time in his life, why, and made his way to Millennium City.

Sometime after the events of the Qularr invasion, David was contacted by the Department of Defense. David began working for the U.S. government as their secret weapon, where he started using the alias, Vitality, with Andrew Rochester as his liaison. David was equipped with an earpiece to receive direct orders from Rochester, enabling him to be where he is most needed.

Vitality worked solo for the government for about a year before his missions forced the occassional team up with the Department of Emergency: Logistics and Tactics Agency. After their missions together became more frequent, the Department of Defense officially placed Vitality within the agency.

Delta was formed when the Department of Emergency: Logistics and Tactics Agency was shut down. When UNTIL wanted to reassign the agents into their various sub-divisions, David and a few other former DE:LTA members took a stand. The bond forged in the agency produced more than just co-workers and together they were not just the Logistics and Tactics Agency for the Department of Emergency, they were Delta, and they meant to keep it that way.

Ultimate

David's best friend Nathan showed up in his hometown with apparent super strength and durability that he did not have previously. Nathan explained to David that he was behind the robot that attacked him. He agreed to a deal with Teleios, to set up the fight between David and his robot, in attempt to get a sample of David's blood for his experiments. Using David's blood as a catalyst, Teleios was able to genetically enhance Nathan, giving him superhuman strength and durability. Nathan attacked David, but the fight ended quickly as David easily overpowered him. Nathan escaped after the fight and went back to Teleios. Wanting him to increase his power levels, Nathan agreed to become Teleios' Ultimate Being of Power. Teleios' new experiment combined David's blood with Draysha compound. Nathan's size and muscle mass increased exponentially, dramatically increasing his power. With his strength levels now incalculable, Nathan betrayed Teleios and completely destroyed the facility. Nathan, now going by Ultimate, began to recruit his very own army, somehow giving power to those who are loyal.

Storyline: Ultimatum

Impact

Downtown Millennium City was undergoing reconstruction after the cataclysmic fight with Ultimate had laid waste to the surrounding area, when a man was found alive under the debris from a destroyed apartment building, after aid workers discovered he was super powered when he was seen attempting to break the debris with some form of energy, they backed up and decided to call in back up. The man once freed, seemed to go on a super powered rampage, blaming Vitality for the death of his family during the fight with Ultimate, and demolishing the rebuilding work that was being done in the neighborhood. PRIMUS was called in and arrived on the scene just in time to stop a man going crazy and destroying anything further, they were able to subdue the man and lock him up in the Westside Prison.

Storyline: Brace for Impact

Theraxian Vanguard

The Theraxian Vanguard is a group of five alien beings from the planet Therax-Prime, sent to earth to weaken it's defense for eventual takeover.

Storyline: The Theraxian Vanguard

After the defeat of the Theraxian Vanguard, they were locked in the same U.S. Government holding facility as Ultimate. However, their unique energy allowed them to compromise the system and break out, and in the process of doing so, Ultimate was released as well.

With the imminent threat of Ultimate and the Theraxians being loose, the U.S. Government started a black ops agency with the sole purpose of doing "whatever is necessary". This black ops group started with the plan to make a deal with Teleios, to have him make a chemical agent strong enough to incapacitate, if not kill, Vitality. Their hope was that if this chemical agent could stop Vitality, it could also stop Ultimate.

With everything in place on Teleios' end, the agency lured Vitality into a hostile area under the guise of requesting his help to take out a VIPER base. Vitality was attacked and incapacitated by the chemical agent and taken by Teleios. Teleios boasted to Vitality the truth about making the deal with the "government" to enact this plan. Instead of killing Vitality outright, Teleios kept him locked up to drain him of his blood for his experiments. However, the rest of Delta were able to track Vitality down and save him before he could be killed.

With their first plan being a failure, and knowing that they alienated Vitality by it, the black ops agency decided to restart a failed government project to create superhumans they could control. The project, named Cyber-Refine, was started to make the cyberline serum better. They wanted it to make their subjects more powerful, and make the serum permanent. However, it was officially shut down when all the initial subjects died of tissue and neural decay. They found the doctor who worked on the initial project, and he found a way to make it work. Using people with dead tissue.

Storyline: The Breakout
Storyline: Parabola
Storyline: Are you having fun yet?

Vitality stayed in discrete contact with Andrew Rochester, who had no idea of the black ops agency, in order to get more information about everything that happened. Rochester used his pull, behind the scenes, to give Vitality details about Project: Cyber-Refine.

Over the course of a couple months, Andrew Rochester and Vitality, with the help of other Delta memebers, were able to piece together information surrounding the project, and it's relation to everything that had happened.

Delta found out that the one successful subject of the project was Tom Winston, a serial killer who was locked up in the Millennium City Prison before apparently committing suicide in his cell. Knowing his previous ties to the Maniac gang, they were able to extract information from the gang in the Westside area.

This information led them to an underground Maniac base in the Westside. They found Winston and eventually defeated him. After everything that had happened, Ultimate and Theraxians escaping after being captured, and now Tom Winston, a serial killer freed again by the government. Vitality took it upon himself to not give Winston another chance at freedom, and killed him on the spot.

Feeling that he was not the person he thought he needed to be, Vitality decided to walk away from it all. He quit Delta, and gave up on being a so called "superhero".

"I'm Done"

A few weeks after David quit being a superhero, his former Delta members, Sarge, Crescentwave, and Psirus, were lured to Canada by a PRIMUS message asking for thier help. When they got there, they were confronted by Ultimate. Sarge ordered Psirus to go warn the others, and he and Crescentwave engaged Ultimate. Ultimate easily overpowered them, and just before he was about to kill Sarge, Crescentwave got them out.

After the attack, Dawn contacted David to let him know what happened, and he came back to the base. They traced the PRIMUS message back to a downtown HQ, and David, along with Dawn, Joule, and Shockwave went looking for answers. When they got there, the base had already been overrun by Ultimate's henchmen. They got things under control and found that the message was relayed to that base from another PRIMUS facility in Canada. One of the henchmen mentioned that the facility in Canada had been taken over by Gidrean, one of the escaped Theraxians.

David and the other Delta members rushed to this facility to find out the truth. They secured the base and defeated Gidrean, finding out that Ultimate is now working with the remaining Theraxian's, and the PRIMUS message sent to Delta was made to lure them into a fight with Ultimate to take them out.

David rejoined Delta, after realizing that he can't save everyone, all the time. He can't be Vitality...but he can still do his part as Variant.

Vitality possesses superhuman abilities as a result of his unique physiology including superhuman strength, speed, stamina, durability and and is capable of flight under his own willpower.

Superhuman Strength: David has the potential to be one of the physically strongest beings in the world depending directly on his confidence and determination. The upper limits of his strength has been theorized to equal a force greater than that recorded on the Richter scale.

Durability: David is nigh-invulnerable to almost all harm. He can withstand extreme temperatures, survive the vacuum of space, and has shown to be immune to most radiation. However, repeated punches of great force, such as those from Ultimate, can harm him over time. If he is harmed, however, David is able to recover from injuries more efficiently and quickly than someone with a normal human healing rate.

Lung Capacity: David can hold his breath in space and under water for long periods of time. It is theorized that he can survive nearly 6 days on a single breathe of air.

Willpower: David's willpower gives him complete control over his mind and body. This not only enables him to fly, but also serves as an innate protection and resistance to all but the most powerful Telepaths and Telekinetics.