Born into a middle-class Gilnean family, Sathestrias Darkhaven spent the first twelve years of his life in Gilneas with his mother, father, and older sister. Near his 13th birthday, however, his family opted to leave Gilneas, though they sadly left behind his already-adult sister, who was already engaged to be married.
When they left Gilneas, they settled in Lordaeron. There, Sathestrias had his first encounter with magic, through a chance encounter with a traveling Kirin Tor mage. His great interest in magic led the mage to suggest that they bring their son to Dalaran to train as a mage, which Sathestrias agreed to when asked by his parents.
From the ages of thirteen to thirty-three, Sathestrias trained as a mage, becoming quite adept at all he attempted. When he would gain a good hold over one type of magic, he would move to another, impressing his professors with his magical versatility.
He moved back to Lordaeron, where he stayed for another nine years before escaping with his mother from the Scourge - By that point, his father had already passed. He took his mother to Stormwind, where they found shelter and Sathestrias himself found employment.
His mother passed soon after their settlement, though Sathestrias found himself not alone soon after; In the aftermath of Gilneas rejoining the Alliance, he was reunited with his beloved sister.
Unfortunately, his sister had been plagued by the curse of the Worgen. In an attempt to make her feel welcome and at home, he willingly allowed her to pass the curse to him, his magical preparation beforehand preventing him from going feral.
His employment consisted of work as a librarian in the Stormwind castle, using his work to read through books about magic and it's history. He found himself longing to know more, and eventually this longing pushed him to pursue dark magic for the first time in his life, leaving all that he owned to his sister as he departed from Stormwind.
He sought out the Black Harvest, who accepted him. He became known for a time as "The Fourteenth" and studied fel and void magic near constantly during his time in the Dreadscar Rift. Eventually, when he felt he had a good grip on his new magic, he chose to depart from the Black Harvest - The Legion was on the verge of total defeat, and he could not do much more for his now-former allies than he already had.
After his departure from the Dreadscar Rift, Sathestrias used his knowledge of portal magic to travel to different worlds. He believed that magic could very well be like animals and plants - Native to a certain planet, with not all types being universal.
He found many variations of the magic he already knew, but this wasn't enough. He was certain there must be more.
And soon enough, he discovered that he may, in fact, be correct.