Story
Backstory - ??? - 3E 427
Hadrevan was born on a certain day to uncertain parents. They remember nothing about their life up until they were an adult-- a fact that bothered them greatly. They drowned their troubles in apathy and partying, soon being drawn to the Cult of Sanguine. In worshipping the Prince of Revelry, they found a "purpose," if one could call it that. They had a way to avoid any responsibilities, have a lot of fun, and ignore their own problems.
After some amount of time, Hadrevan's time in the cult is cut short. Something goes terribly wrong at a party they're at-- so they think, they don't really remember-- and they spend some days on the run before being apprehended in Kvatch. But to their surprise, they weren't just thrown in prison-- they were forced onto a boat, deported to Morrowind.
Story - 3E 427 - ~3E 430
Hadrevan was essentially forced to work for the Blades once arriving in Morrowind, as it was apparently their repayment for being freed. They were just glad to not be in prison, and instead blew off all the duties given to them by their superior, Caius Cosades. He tried whipping them into shape, but nothing could impress any urgency on them.
They spent a lot of time at bars and clubs, much like their previous life-- just without the outright Sanguine worship. And there, they met a girl-- a barmaid called Varassa, a beautiful Khajiiti woman. Hadrevan didn't intend to fall in love, but it came so fast. During this time they kept working for Caius, and they eventually learned that they were supposed to be the "Nerevarine," some folklore hero, or something. They brushed off that notion, despite the disturbing dreams that plagued them, where a man in a golden mask would haunt them...
Their destiny would metaphorically punch them in the face one night. After blowing them off for so long, the Sixth House became irate, and kidnapped Varassa. Hadrevan wasn't able to save her, and walked away guilt-ridden and diseased-- as one of the priests had cursed them with Corprus. They returned to Caius, hoping for comfort, and instead realized he'd been manipulating them the whole time. They were truly alone.
From then on their personality changed severely-- they were now cold, driven, and even brutal. They followed the prophecies closely, doing whatever it took to become Hortator and Nerevarine. They allied themself closely with the Ashlanders. They spoke with Vivec to get insight on defeating Dagoth Ur, but made it clear they wouldn't let him get away scot-free.
And when Dagoth Ur was defeated, they planned to kill Vivec next-- but business led them across the sea to deal with Almalexia. That was fine for them, as they needed to kill her and Sotha Sil as well-- but they found that Sotha Sil was already dead, and entered a battle with Almalexia. Once she was defeated, they returned to Vvardenfell to put an end to Vivec.
Post-Morrowind - 3E 430 - 4E 201
Hadrevan disappeared shortly after killing Vivec, their whereabouts guessed at but unknown to the public. They returned full-force during the Red Year, working diligently to protect as many people as possible. They'd spend many years afterwards helping dunmer immigrate to Skyrim and Solstheim.
After some time they seemed to vanish again-- though nobody really knew that they were still on Solstheim. Their presence was only noted again when the Last Dragonborn, Ragnar, came to Solstheim to investigate a cult trying to hunt him down. They took up the mantle of "hero" again to help it. Once the threat of Miraak was dealt with, Hadrevan re-entered the public eye again, acting as a guardian against dragons that would threaten Solstheim or Vvardenfell.
