Corbin is from the “Eclipse Phase” setting. The books are available for free here. Basically, this is set in the near future, where humanity has screwed themselves over in a variety of ways, but still clings to life.

Corbin spent a great deal of time designing and building artificial bodies for people to sleeve into. This involves a great deal of robotics and biology design skill.

An agent of the elusive organization known as "Firewall," Corbin spent a great deal of time using his skills as a body builder for individual jobs for sentinels. However he also has been called upon to investigate strange things, or just kill outbreaks where he was the closest one available.

Corbin was a spacer from birth. He was born in a habitat in the asteroid belt, and fitted with neural augs as he aged. His parents were early level autonomists, pushing for a new way of life in space. Corbin underwent accelerated learning programs in experimental simulspace, getting him used to the out of body experiences that would become common later in his life.

It was a pretty peaceful existence, right up until the Fall. Back on Earth, political instabilities were building, until a group of hyperintelligent seed AIs (ASIs) called TITANs revealed themselves and promptly began wrecking everything. Nobody is quite sure why they did this, but they began to forcibly upload as many people's minds as possible. Then, just as quick as they appeared, they vanished. But the damage was done. Earth was effectively uninhabitable. Weapons of mass destruction had devastated basically the entire surface. 98% of transhumanity didn't make it out with their hides, many simply took uploads of themselves and sent them out to places in the solar system while their original copies stayed behind and died.

Corbin decided to do what he could to help the lost souls of transhumanity, and found a passion in morph design. Following in his autonomist leanings, he released many of his mod designs as open source. Of course, he still was able to build up quite the reputation as a body-builder (pun intended).

He started out just making fun aesthetic modifications to existing morph designs. Simple things like changes to faces, voices, and other typical human features. He started experimenting with more advanced changes soon enough. Thanks to the ubiquity of free information available out in the Belt and beyond, he spent time learning new skills related to his bodybuilding. Soon he was starting to work on adding cybernetics, biomods, and even experimenting with neural improvements.

As transhumanity began to re-establish itself, he went over to the massive asteroid habitat “Extropia” and set up shop in the growing “Vat City” district. While he did release many of his designs as open source, there were plenty of people who wanted his expertise in building custom bodies. Originally he worked with biomorphs, but found that switching to synthmorphs was a much more liberating experience. Synthmorphs didn't have to worry about things like organ placement or proper blood flow, and were considerably quicker to fabricate.

Proximity to the heavily bioconservative Jovian Republic put a bit of a damper on his popularity. Even belters couldn't get over the whole stigma of the clanking masses. Corbin sought to change their views though by starting to focus on stylish, high performance, high quality synthmorphs.

Corbin began taking house calls, as it were, to head out to distant habs to do commission work for exclusive customers. He even made it as far in as Venus and Luna to work on some highly customized steel morphs. But he always returned to the belt.

4 years after the fall, he suddenly found himself waking from a 2 month old back-up. His original body and even the entire habitat he'd been working at had mysteriously been destroyed and nobody seems to have any idea why. Rather than try and recreate his old body (He had a full read of his DNA attached to his backup service), he decided to try some of his own morph designs. He's been bodyswapping fairly often since.

A short while after he'd been remade, he was contacted by a clandestine organization called"Firewall." Apparently, whatever had happened in his old habitat, it got the attention of some of their agents. Firewall is dedicated to protecting transhumanity from further extinction-risks (x-risks) and seeks to protect them from things too dangerous to be known publicly. After all, in an age where anyone with a nanofab can create anything, they don't need to know the exact composition of a nanoplague that wiped out thousands of people.

Corbin's skills at morph modding were potentially useful, and he had shown bravery and level headedness as, apparently, a horde of killbots got unleashed on that habitat. Corbin took up Firewall's offer and became a sentinel.

Corbin moved out to a "cargo" ship travelling between locations in the outer solar system, The Second Opinion. This was actually a ship "procured" by Firewall to respond to threats that it could reach. In spite of being based on this ship, Corbin egocasted (Sent a digital copy of his ego out) to a number of different habs to spend time on. He continued to build up his reputation for high quality body sculpting.

For the first few months, Corbin simply gave his assistance to Firewall by reverse engineering proprietary morphs like early model Reapers and designing new morphs for their sentinels to blend in or go on ops with everything they could manage. The understanding of tech design he started as body sculpting even let him contribute to a handful of other tech projects Firewall had going in the background.

Then came the time of Corbin's first combat operation. Nominally, Corbin wasn't considered a combat asset for Firewall. But when a hab out in the middle of nowhere reported that they were under attack by some kind of monsters, the Second Opinion was the only Firewall asset close enough to respond in a timely manner. He and the other sentinels aboard took morphs over to the habitat while the Second Opinion waited at a distance. Once inside, they were greeted by the rather horrifying discovery that Exhumans had taken over the hab. Exhumans are a group obsessed with evolving, and are always pushing new mental and physical modifications. They more often than not created monsters in this process. Turns out a few of them had infiltrated here and claimed it's citizens as inferior cattle to be devoured. And of course they had done horrible things to their bodies and minds as well. Luckily for Corbin, he got killed fairly early on in the operation, so didn't have to deal with the worst of what they had to offer. His cortical stack (mind backup device) was recovered and he was remade aboard the ship and spent a while in the care of a Firewall therapist.

Corbin almost decided to quit firewall if he knew it'd lead to more scenes like that. But after some self reflection, he realized that him quitting would mean he'd just be like one of those victims sooner or later. So slightly out of desire to do something, slightly out of desire for a form of self preservation, he decided to stay in firewall and start doing training programs in addition to his body modding activities.

Some of these training programs were basically well designed realistic games, such as the popular one “Breakout” where the subject has to survive and escape Earth during the fall. Others were fully militarized simulations and skill-softs, meant to train people for all kinds of scenarios where violence might occur.

Fortunately for Corbin, he wasn't called upon for violence for some time. When he was, he proved to be a much better asset to his team. The mission was a success, all they had to do was take down a low level AI that had gone off the rails and was trying to convert the mass of the habitat into more identical habitats. One might see where the math fails in this, but that's limited AIs for you. Hundreds of blown up robots later, Corbin got a case of beer and a whole bunch of reputation points.

In the outer solar system, TITAN machines weren't as big of a problem as fringe groups were. Criminal gangs trying to procure dangerous items, exhuman cults dedicated to massive mental and body manipulation (more often than not creating monstrosities), and strange dangerous relics coming through the Pandora gates (Stargates built by an unknown entity leading to other planets). Corbin became a fairly active sentinel, and took on all sorts of problems. He's egocast as far out as Pluto, and has gone through the Pandora gates a handful of times.

As the last few years went by, he's spent an increasing amount of time working on morphs that integrate to weapon systems. That's the idea with Rex-14 and it's customized battlesuit. He was on a habitat dealing with an Exhuman nutcase's unknown artifact, and encountered hypercorp mercenaries attempting to obtain it first. This was where he was when he was migrated in, bringing a damaged Reaper in with him.

This battlesuit was designed specifically to augment the Rex-14 morph. It grants considerable armor capabilities, and has thrusters to allow it mobility in microgravity. It also augments Rex-14's existing considerable strength. It has several mounted weapons.

Corbin's Muse "Spiffy" is an AI assistant, designed to operate at limited intelligence actions. It rides along with his brain and can be downloaded into appropriate hardware.

Corbin arrived with a basic set of tools for providing field repairs to his morph and weaponry.

Corbin came in during an operation that was turning violent. He had a railgun rifle with seeker missile attachments, laser pistol, and monoblade knife.