Mya had grown up to become a mage of Lordaeron, but she never traveled to Dalaran for her studies, and all of her skills in magic were quite minor and fairly unremarkable. Her studies were further distracted when her future husband, Oswald, courted her to the point of eventual marriage. The two had conceived a child together, whom Mya wanted to name "Allose" because it seemed to have a nice ring to it.
With raising Allose and now having a family, alongside a man who would become a commited soldier of Lordaeron, Mya had to abandon her studies of magic to ensure that she could take care of Allose each passing day. She was disappointed to be left with the position of the common mother stereotype, but she rested assured that it was still for the best of her new family.
Allose had grown to the age of about ten, attending to his studies in the house while Mya was outside tending to some matters. At this point, the Scourge had emerged from Lordaeron to attack the populace, and a pair of ghouls attacked her. She had no means to defend herself, and was tackled to the ground as the ghouls ate her alive. Though Oswald was there to beat off the ghouls, it was too late for Mya, and she slipped into unconsciousness as death took hold.
However, death was not a luxury for her to take. The injuries from the ghouls only gave the Plague of Undeath on to her, and resulted in her eventually rising from her own pool of blood. To her surprise, she had kept her own will, and was horrified at her new state, yet was forced to serve the fallen prince, Arthas, all the same.
In her undeath, Mya tried to restrict herself from fighting. She deliberately hung back in assaults where the control of her body was lax, to avoid causing harm to innocents, despite how futile the very gesture was. Still, through her strong willpower, she was determined to not be a slave to the Scourge.
Eventually, that willpower won through. The Lich King's power over her waned, and her body was soon her own. She heard mention of rebel Undead, now called Forsaken, gathering near Lordaeron city. She immediately ventured there, and joined the ranks of the Forsaken. She still could not understand what to make of her new condition, but she eventually resolved that she would still make an attempt, at the least, to find her family.