Sergeant Joanna is involved in the quest The Conspirators. She offers the job to Hawke after trying to get permission from Marlowe Dumar with no success. She then gives a list of names and descriptions to Hawke and states that she'll reward Hawke if any of the listed persons are killed. She later reminds Hawke that despite being given the job, Sergeant Joanna might beat Hawke at killing the conspirators.
Once they are killed, she returns home.