[Many trigger warnings apply. See this post
Seth is an only child, born and raised in Manchester in a working class family, and his parents divorced when he was a boy. His dad was emotionally absent, and his mum worked two jobs - which was better than being unemployed, certainly, which was fairly common back then - so he spent a lot of time on his own. They lived in a council flat, in a poor neighborhood, where gang activity, drug trade and gun related violence was pretty common, particularly during Seth's early teens.
He managed to keep himself in school throughout most of his teens, but the education system didn't really work in his favour. Due to a combination of lack of motivation, concentration problems, and somewhat troubled home life, he flunked out of school and never got his A-levels, even though he was smart enough to have managed it if his circumstances were better. He had a couple boring jobs that didn't really teach him much - except for being trained in first aid by St John's ambulance, but that's pretty much it.YOUNG ADULTHOOD:
In his early twenties, he started dealing drugs. Mostly small stuff to begin with, stuff for his mates, but he enjoyed the excitement he was unable to find elsewhere, the money was good, and he was good at it. He was actually really good at it, and wanted to be the ultimate dealer.
He had a few girlfriends. A childhood sweetheart, a relationship that seemed very important at the time, the way it does when you're young, but who was ultimately very unsuited for him. As he started dealing drugs, he suddenly attracted a lot more girls, and he ended up falling in love with one of them, until it turned out she was only really interested in him for the money and access to drugs. After that pretty upsetting breakup, he moved to London and set up shop there.
Seth had decided girls weren't worth the trouble, and were bad for business, and then a few months later he met Shannon and he fell for her hard. She didn't even seem to like him at first, but it turned out she preferred his more sensitive, gentle side than the tougher, confident persona he was projecting. They were together for over two years.GETTING HIS POWER:
Then the Storm hit, sudden and intense. Seth was struck by a bolt of lightning that gave him his power, though it took him a while to realise, as his power only did anything when interacting with other people who had powers.
Not long after this, Shannon ended up ODing on drugs Seth had given her. He's never stopped blaming himself for her death. He was a mess after she died, sulked, got drunk, got into fights, and generally had a bad time of it. It's debatable whether he gave up drug dealing because of what happened to Shannon, or because he simply wasn't in any state to do it anymore.
A few months after Shannon died, he discovered what he could do, quite by accident - someone was attacking him using the power of super strength, but they never had time to hurt him much, as Seth sucked the power out of him in self-defense. He realised he could put this new-found skill, not to mention his experience with dealing, to good use. He eventually gave the strength power to his bouncer, once he opened up a place where he could buy and sell powers. Since then he's been looking for someone with the power to bring back people from the dead.EVENTS OF CANON:
He eventually got the Misfits (a group of superpowerer youths on community service) as customers, though he kept out of their business even when Kelly came to him for help. She later helped him fix his car when it had broken down, and then made him buy her a drink, and they flirted. The next time they met, Seth rejected her offer of a date, still not over Shannon, and had to admit this reason to Kelly. A week later, Kelly came and told him that she'd been to an alternate timeline where Seth was kept prisoner by Nazis, and him and Kelly had fought them together. The alternate Seth had then kissed Kelly just before dying. The news of this spurred the regular Seth into finally asking Kelly out. His search for a resurrection power had continued to turn up nothing, and he tried to accept that he couldn't keep mourning forever.
Of course, it didn't go smoothly, as Kelly ended up standing him up - but for a very good reason: she had swapped bodies with a girl in a coma, and Seth and the gang had to rescue her. After that, though, they had it nice for a couple of weeks, Seth even inviting Kelly to come along for a holiday. She turned out to be exactly what he needed, perceptive enough to see through his shell of self-preservation, and stubborn and caring enough to break him out of it. She also challenged him and made him remember his damaged idealism, making him a better person.
But then his search for the resurrection power paid off unexpectedly, and Seth couldn't say no. He had
to bring Shannon back, because it was his fault she died - he had to repair the damage he had caused. He told Kelly he had to stop seeing her because Shannon was alive again. Unfortunately it turned out that anyone brought back this way turned into a zombie - not rotting and shambling or brainless, but definitely with a craving for human blood. When they found out, Seth first tried to make it work, having her feed on animals, thinking it was better than nothing.
Unfortunately it soon became evident that Shannon was unable to control it, when she killed their neighbour, and he knew to his despair that she had to die before infecting anyone else. However, he was unable to do it himself. Shannon had more control of herself because she was brought back, but people infected by her were more or less mindless monsters. Soon the gang had the start of a zombie apocalypse on their hands, and they had to kill a few dozen zombies to avert disaster. Seth also had to come to terms with the fact he also loved Kelly. Shannon overheard this, and tried to kill Kelly, and Seth ended up killing Shannon to rescue Kelly.
After those events, Kelly convinced Seth to stop dealing powers because of the serious consequences it could have. The death of one of their friends made them decide to take a break from the worries of London, and they went on vacation to Uganda together. While there, Kelly used her powers to defuse a land-mine, and they decided to move there. Seth went back to England to pick up the rest of their stuff.
While back, he ended up being affected by a guy's powers to become completely obsessed with a suitcase of money and lose any kind of conscience. Him and the gang did pretty terrible things to each other and others while under the influence of this, including Seth pretty intensely torturing a guy. Thankfully it didn't last, and they ended up not hurting each other too badly, though Seth definitely has some issues with having his mind meddled with after that. The gang convinced him to come out of retirement to take one last power, and then he went back to Uganda to stay with Kelly.FALLING THROUGH THE RIFT:
On the plane ride south, Seth ended up getting sucked up by the rift, and landed in New York on the 10th of October, 2012 - a few weeks back in time, but in a universe where he knew no one. He was immediately taken in by the rebels, who provided him with money and shelter. When they discovered his powers not long after, they convinced him to work for them, putting a rather idealistic spin on things. He hoped that using his powers for a good cause, helping the Rifties, was a much better plan than just doing it for money. At first it was alright, but he ended up being part of things he didn't approve of, and as he started questioning their methods and motives, a few really shady things were done to keep him there, including heavily implied threats regarding the safety of friends he'd made.
On November 12th, just over a month after he arrived, he warned the people he'd befriended, then tried to make a break from the city. He made it to Jersey when he was hunted down. They attacked him in an attempt to capture him, and in self-defense, Seth ended up accidentally almost causing the death of a rebel. This was enough for them to deem him a danger to others and lock him up, while still making use of his powers. The people he'd befriended assumed he had made it out of the city.
He was held prisoner for almost four months. He was given the designation J-19-5-20-8, which he also had tattooed on his back at one point as a reminder that he was stuck there. During this time, he was severely dehumanised, neglected, abused, exploited and experimented on. Just how badly depended on whether he behaved and followed their orders. He tried to escape several time, and he tried to commit suicide twice. They also discovered that morphine made his powers stronger, and also made him more compliant, another way to control him, and he eventually developed a dependency on it as a result.
Eventually he developed the ability to use the powers he was holding, and he assumed it was a result of the morphine. He kept this secret until he got hold of a power he thought he could make use of. Finally he got hold of the power of phasing through walls or objects, and he took his chance. On March 7th, two weeks after his 29th birthday, he managed to escape from the base. At this point he'd been in the city for about 5 months.START OF GAME:
As soon as he got out of the base, he bumped into the archangel Gabriel, who teleported him away and offered him refuge. Seth left early the next morning, not trusting anyone, and needing to make sure Gabe wouldn't do anything to keep him there. It took him a little while to remember the basics of how to function on his own, and he kept on the move, stealing what he needed, and phasing his way into empty hotel rooms to sleep. He also continued his morphine habit, scared his powers would go away if he stopped, and also using the drug as an extra coping mechanic. After about a week he returned to Gabriel, deciding he was trustworthy enough. After this, he often spent the night on Gabe's couch, when he didn't want to be on his own.
He soon got an apartment of his own, down in the financial district. Most of his efforts for the next few months went towards two things. One: readjusting to society, slowly trying to rid himself of the conditioning and trauma he'd gone through at the base, coping with his PTSD. He eventually moved his income source from stealing to drug dealing. Two: getting more powers to ensure his continued survival. This one was a bit trickier. While he had certainly been damaged and hardened by his imprisonment, he refused to do anything outright immoral to achieve his goals. He took a healing power off a rebel he knew didn't deserve to have it. He also took the teleportation power of a willing Peter Vincent who wanted rid of it, though Gabe made him give it back later.
Near the end of May, Gabriel called upon him for help, to fight... an actual Godzilla. Seth was pretty miffed when he found out the giant lizard had been an illusion all along, and that Gabe had even faked his own death just for dramatic effect. Then again, Gabe was pretty miffed that Seth was selling drugs, though he was mollified upon learning it was just pot, rather than anything harder. A while after this, Seth moves into an apartment underneath Gabe's, as he had bought an entire building and lets Seth stay there for free.