Joanna is one of Robyn's most loyal and devoted followers, as despite graduating from Atlas Academy and having the option of obtaining a high position and high paying job in the Atlas Military, she instead chose to follow Robyn to Mantle and help her fulfill her goal in improving the Cities economic and living conditions, a goal that Joanna has become very committed to, as seen in the events of "Sparks" where she would not even shy away from resorting to criminal methods to help repair the cities outer walls, as seen when she assisted her leader's attempt at robbing the convoy transporting the resources to a top-secret Atlas military project, showing that she was more loyal to Robyn than that to her own Kingdom.
Joanna's closeness to her leader is also further demonstrated during the events of "A Night Off" where she assures Robyn that she would win the election, showing her immense faith in her leader's skills as a politician and the righteousness of her cause.
Fiona is Joanna's teammate. They are almost inseperatable and they are rarely seen appear most of the time.
In "Pomp and Circumstance", they can be seen spying on Atlas military, and later work together with the rest of the Huntresses in "Sparks".
Joanna and Fiona share a friendly relationship as seen in "Refuge", in which Joanna puts the upmost faith in Fiona's ability to coordinate the Huntsmen aiding in their plan to keep the civilians of Mantle safe in its crater. Similarly, Fiona is playful with Joanna, asking why she isn't leading that effort after the taller Huntress took charge of their mission.
In "Risk" Joanna helps May comfort Fionna after she broke down in tears after Ironwood destroyed the Schnee Dust Company ships and threatened to bomb Mantle if Penny doesn't surrender herself to him, showing herself to be protective of her teammate.
Joanna is May's teammate.
As the apparent acting leader of the Happy Huntresses, Joanna sends May to work with Ruby's Group, confident that her teammate would be able to sneak into the Atlas Command Center without being captured. She is proven right as the group manages to escape without major losses.
The two later work together to help the people of Mantle in the crater, and comfort and hug Fiona together after she broke down in tears.