Sulwyn Sunmantle was born in the area that is now known as the "Ghostlands" (while her family was there visiting relations). Her father was Lord Helius Sunmantle IV, and her mother was the Lady Solaris Sunmantle. Sulwyn, like many children in her social circle, was spoiled rotten as a child. Her father Helius doted on his youngest daughter whenever he could get the chance to, always buying her expensive gifts and allowing her much more freedom than his other children. Eventually, Sulwyn's mother had insisted that she get an education, like her other sisters, and had enlisted the help of some "old friends" to get Sulwyn to a seminary to study. Also at the seminary Sulwyn's sister, Sunna, was studying the final years of her Priest training, along with Theophilus Falthrien .
After her successful departure (and a dubious double-life and marriage) from the seminary, Sulwyn began to use her newly-found skills in Outland, aiding injured war victims there. While in Shattrath City, she was approached by an older Quel'dorei woman that had informed her of a religious order known only to outsiders as "the Sisterhood". Curious, Sulwyn had pressed the woman for more, which resulted in Sulwyn finding out the truth about her maternal family's past, and her "birthright"; she was the end result of a long, and carefully-planned breeding program (whose true, sinister purpose was kept hidden from her). Stunned by the revelation, Sulwyn pressed for further answers, only to be told that she must join the Sisterhood, or risk losing her husband's life. She refused, believing she was powerful enough to eliminate any threat made against the peaceful merchant's life, only to see him driven insane by their agents, wandering away into the deserts of Durotar to die.
Unable to cure her husband's insanity, she pleaded to the Sisterhood for a cure. She was then asked once more to join the Sisterhood, and Sulwyn had unwillingly accepted, under the notion that her husband would be restored to her once more. After many months of training and subsequent brainwashing, Sulwyn was told that her husband had been killed and eaten by desert predators, and was given an "assignment" to work on. She had been told to focus all of her efforts on a promising, and talented magister, and to bear him children. Weak and powerless against the months of brainwashing and drugging, she had reluctantly obeyed and had courted and married Ethilien Arberon. Eventually, she unexpectedly began to love him as deeply as any wife would their husband.
What the Sisterhood didn't expect was Sulwyn's apparent infertility when she had failed to conceive the "specimen" for their breeding program. Desperate for their end product, the Sisterhood had put Sulwyn on a massive Fel-consuming regiment. Over a few weeks, the daily Fel-crystal tapping seemed to work, and Sulwyn was ready to produce the final stage of the Sisterhood's eugenics program. However, since her child would be conceived using large amounts of Fel-energy as a fertility treatment, the resulting being would have a high-risk of becoming Fel-poisoned, with symptoms similar to those Fel-tainted Sin'dorei known as Felblood.
With the risk of her child becoming corrupted, Sulwyn decided to come clean with Ethilien. At first, he was infuriated for learning of her deceit, but when she confessed that she had truly fallen in love with him, they had both decided to escape the clutches of the Sisterhood and fled to Tanaris. There, while Ethilien was out gathering food, the Sisterhood had ambushed Sulwyn and told her to hand over her newly-birthed twins, Solanas II and Sephiren. Believing that resistance was futile, and that the Sisterhood would eventually find them anyway, Sulwyn willingly gave up her twins to them. Ethilien, upon hearing about her apparent apathy, became infuriated and left Tanaris, leaving Sulwyn alone and destitude for her apparent "betrayal".
Racked with guilt, Sulwyn now wanders around the deserts of Tanaris alone. Unable to handle the magnitude of her decision, she wanders the vast dunes in hopes that one day the desert itself will consume her, giving her some sort of crude redemption for her mistakes.
She was last spotted wandering past various scattered outposts in Southern Tanaris.