Roah is an unscrupulous trader who has come to the goblin camp with the intention of buying goblin prisoners as slaves and selling Smokepowder. She is disappointed that the goblins are no longer willing to sell their prisoners, since they are now sending them to Moonrise Towers. She is more than willing to trade with the party, if they have coin.
Roah can be found west of the central chamber of the Shattered SanctumX: 275 Y: -29.
Act Two
The Zhentarim traders can be encountered again in the entry hall of Moonrise TowersX: -174 Y: -176. Roah mentions the lucrative smuggling she does for the cult of the Absolute. Rogues receive a special dialogue option to use Thieves' Cant to ask for a discount.
Act Three
After the party has encountered Minsc and 'Jaheira' in The Counting House, Roah can be found making a deal with 'Jaheira' in the Abandoned Cistern portion of the Lower City Sewers. Initially, she is part of the battle that ensues. However, if not immediately killed, she takes the opportunity to flee the sewers.
At the Guildhall, Roah and her Zhentarim have staged a coup, attempting to replace Nine-Fingers Keene as leader of the Guild. If Roah survives this conflict, after the battle, she will move into the former Guild Master's office and resume being a trader with her existing inventory.