Tallie was one of two offspring born to Noana Sowrs, who served as Sector Constable on the planet of Taris. Along with her sibling, Nahk, Tallie was abducted by Brejik and Griff Vao. However, the pair of kidnappers never had the opportunity to demand a ransom because riots erupted across the planet due to Zayne Carrick's escape and the withdrawal of the Jedi.
The two siblings were discovered after Griff's younger sister, Mission, and Zayne, who had come back to Taris, observed Griff delivering provisions to a storage container located in the Lower City. Gadon Thek, who was the leader of the Hidden Beks, gave the children back to their mother in exchange for assistance to help the resistance against the Mandalorians who had invaded and taken over the planet.
As the Mandalorians commenced their assault on the Resistance, Noana dispatched the children to their father, who was residing on Alderaan. Tragically, Noana later succumbed to the Rakghoul plague.
During the writing process for the Knights of Suffering story arc, John Jackson Miller contemplated incorporating his own children's names into the characters of Nahk and Tallie. Nevertheless, when he began writing the next story arc, he changed his mind and decided against using his children as inspiration, giving the characters different names, since their mother, Noana Sowrs, would be transforming into a rakghoul.