Thornton was a calculating agent with huge ambitions. She wished to further the Zhentarim cause by taking over Phandalin and adding it to their territory. Thornton wished to do this by slowly establishing her guild as the governing body of the village.
The fierce woman was not harrassed by the Redbrands, the local outlaws, even though all the other businesses seemed to be. She desired to control the Redbrands to bring the town under her iron fist.
Thornton owned a house to the southeast of the Miner's Exchange.
In 1491 DR, Halia wished to exploit adventurers that had come into town. She would tell them the location of the base of the Redbrands, and where they loitered, as well as offer them a reward for their leader's head. Halia hoped that she could use this information and the reward as leverage to control the new adventurers into doing her bidding. This way, she could assume leadership of the Redbrands.