Rhett expected to be a doctor from an early age. Both of his parents were: Jill and Luke Thorne were both successful doctors in New York, so it made easy sense. Rhett was an inquisitive, social child, born in 1990. Friends were easy, games were fun. He liked sports. There was some stress growing up, as his parents continually thought about divorce (loudly, though not when they thought he could hear), but his family stayed together well enough. In an attempt to regain the spark, his parents ended up having twin girls, that were fifteen years younger than he was, in 2004.
His baby siblings were just two in 2007, when the solar maximum spike across the world awakened Rhett's ability. He was 17 at the time. His first awareness of it was very low-key: all his drinks were watered down, from him purifying the water. It was interesting and weirdly shameful, so the boy hid it at first. It was easy, since his parents had twin toddlers to deal with. He'd go on to hide it for a few months, before he realized he could breathe water, and he told them at that time. They decided he should hide it, since it was so easy to pretend it wasn't there, which instilled in Rhett a great deal of shame over it. He entered schooling to become a doctor, as he graduated high school.
But then the events of 2010 hit. Rhett's parents did what they could, working long hours in the hospitals throughout the wars. He'd pitch in, mostly running supplies here and there to people that needed it at first. He picked up odds and ends of survival skills: from helping to repair wiring to restore power to homes, to making a quick meal, to helping an injured man hang on long enough to get to the hospital.
It was a natural place to join the ranks of first responders, during early 2012, only to be faced with a tide of US military forces and mass executions. But Rhett would go another direction. The war, and a city in collapse, causes extreme infrastructure problems. In addition to issues with electricity, gas, even fresh water and food supplies, there's a big element that most people overlook until they're up to their eyeballs in it: waste management. A city rather literally turns to shit, if the systems don't work. Rhett ended up being collected into a crew of about five men, led by a man named Jem Arlin, to get the sewers and waste system working for the hospitals. They were successful. Jem ended up dying, shot in the street during a clash of other groups, but a lot of others began to look at the hospitals, to find out how they got their waste sorted out. The 'plumbing' group, now led by Rhett and his partner at the time, began to go all over the city, fixing everything from police stations and military locations to private, rich homes. The access was incredible: nobody turned away the plumbing crew. They branched into fixing gas lines and electrical problems depending on who they had, but mainly tried to keep buildings operational. Some fame came with it and a lot of appreciation, as waste management is something people take for granted until they're using a reeking bucket in the freezing back yard.
Other groups, smugglers and criminals, began to clash with Rhett's group, though. They wanted to use the access, and began to dump corpses into functional sewers to prove their point about it. It led to a nasty altercation between Rhett's group and a particular criminal that was trying to operate in their zone. Rhett's challenge to them to clear out only caused most of his crew to be murdered, and Rhett himself was hunted for about a month before he was finally netted out of the water. They sliced his neck up on both sides, mocking his hiding in the water to give him his 'gills', and left him to bleed out. He would, in fact, be found (by Ferrymen, though he wasn't aware of it), though the route back to health was slow, and he would bear the nasty neck scars from then on.
The criminals would later press on him again, but this time he was smarter: he learned what they did, and began to undermine them by doing the same smuggling jobs, but better. As one of the few remaining wartime plumbing and waste crews, he had a lot of access and freedom. He had light but not direct connections to Ferrymen: they were in a related orbit and he didnt block their activity, but he also stayed out of it. They knew him, he knew them.
His own notoriety grew, and the story of the neck scars became told as one of him having done it to himself to show how unkillable he was. Rhett was more a master of his fate now, and lived life with greater safety, doing the jobs he felt still fit with his morality. He didn't like to maintain a crew: not since he got the other one killed so foolishly, but always seemed to end up with some young people around him that wanted to learn how to fix the city. Occasionally criminals pushed on his turf, but learned it was better not to, or they'd have sewage exploding in their base. It was better to just leave the plumbing crew alone or stay friendly: might need them.
Towards 2013, Rhett had became a river smuggler part-time. He knew the rivers, he knew the edges of the city, and he had connections. Over time, he had his own boats, his own supply lines and trade links, using his reputation and access. He could get things: forged registration cards, weapons, safe water, food. He kept caches where others couldn't find them, hidden in the water. He's had his share of nearly-caught, but always manages to silver-tongue out of it. At least, so far.