Ren

"There's no better moral compass than guilt and fear."
Ren Goguen is a warlock adventurer and demonologist.
==Description, etc==
Close to 5’7”, Ren's slim frame holds an athletic build, slight feminine curves balanced by the toned, trim muscle of a gymnast or an athlete. Her skin is pure white, offsetting her piercing red eyes (which also glow, funny enough) and black hair with a dyed green streak. 
Occasionally, wings and horns appear to reveal her true demonic form. Her robes are heavy and loose to allow room for her demon and worgen transformations.
As a worgen, she's remarkably tall, gaining a good foot and a half, some muscle (underneath a layer of black fur), and maybe something else that we don't need to dwell on because we're classy and not pervs. The green in her hair vanishes with her thickened mane, but her eyes still glow.
==Backstory==
Ren was born in Dalaran, during the faint respite of peace between the Second and Third Wars, the only child of Merrick and Jouana Zariel, high-ranking members of the Kirin Tor. They were hardly Council of Six material, but certainly known and respected mages. Naturally, they wanted their daughter to follow in their footsteps, and weren't shy about expressing this. Almost from the moment she could form a sentence, she was enlisted in a prestigious magical academy, had apprenticeships lined up with various reknowned magicians, and, as a slight casualty, the absolute loss of any control in her life. The girl's parents swore they would make their daughter the greatest Mage Azeroth had ever seen, or die trying.
Mr. Menethil favored the latter.
In the aftermath of Dalaran's destruction at the hands of Archimonde, Ren was rendered an orphan, lost in the chaos of the attack. When the barrier went up, Ren receded into Dalaran's underbelly, teenage rebellion and her unstable emotional state leading to the young magician signing a pact with Revana of the Azure Flame - a demon. A substantial portion of her inherited magical artifacts, and her eternal servitude (at an unspecified later date) in exchange for power over fel magic. "It sounded like a good idea at the time" doesn't begin to cover it.
While substantially more powerful than someone with her age and experience has any right to be, the Warlock found herself paralyzed by fear. While the terms of her pact ensured that, beyond the natural addictive qualities of demonic magic, she wouldn't be used as a pawn: slowly corrupted as she grew in power...how could she be sure? What's to say by making this deal, she'd already ensured her descent into madness? As this new terror took hold of her, the city she'd spent her entire life in was transported above Northrend, and the shield around it removed. Ren almost immediately took off for the outside world, desperate to find someone that might be able to give her guidance.
==In-Game History==
While exploring Elwynn Forest at the behest of a warlock coven hidden in Stormwind's mage quarter, she met Millenia Antares, a Mage of roughly her age that quickly befriended Ren, despite her less-than-savory power source. The two grew close quickly, and traveled most of Azeroth together, eventually joining the Saviors of Sanctuary, a militia dedicated to upholding justice, freedom, and virtue for all of Azeroth. Millenia's friendship, in addition to membership of a group that was, by definition, "the good guys" seemed to assuage Ren's fears, and she grew even more powerful, participating in several major battles across Outland and Northrend with the Saviors.
And that's about when Revana decided Ren had grown enough to be useful as a minion. She possessed a schmuck that had called on her without forming an actual pact, and tracked the Warlock down to deliver an ultimatum: Abandon the Saviors and serve her as a member of the Burning Legion, or face all the wrath an ancient Eredar witch can bring on a puny mortal. Which is, by the way, a lot. Our heroine's desperation got the better of her, and chose to 'run the hell away' by burning out her host. At the end of a prolonged battle, she had succeeded in substantially weaknening Revana...at the cost of said host, whose identity had been utterly annihilated. Even the afterlife or undeath would elude him without a soul to anchor her consciousness.
Wracked with guilt at what she'd done, and fearful for what might be brought on her as vengeance by the demon - or worse, her victim's friends and family, she fled the Saviors in disgrace. Her few friends, upon learning what she'd done, almost unanimously abandoned her to her fate, and she now lives alone in Dalaran, occasionally peeking out to participate in a Council of Six operation or investigate some strange goings-on.
It took a long time, but eventually, Millenia forgave Ren, though her guildmates weren't so pleasant about it. Working freelance, Ren and Millenia were instrumental in the destruction of the Lich King, and then the rescue of the Ruby Sanctum. For a brief time, all was well. And then the Shattering happened.
While evacuating Gilnean refugees, Ren was bitten by a berserk worgen and bitten. Oh teh noes! Lucky for her she found a new guild to put up with her weirdness as they adventured across Azeroth, righting wrongs and doing general goodery. Is that a word, goodery?