Jess was Kestrel's best friend. She barely survived the Herrani-Valorian revolutionary war.
Jess is described to be quite cheerful and friendly. She loves dressing up and seems to be a loyal friend, as she will stay loyal to Kestrel, even when she'll have a reputation ruined (something that Benix won't do). Even though she seems to be a nice girl, we can see that she contains within herself a dark side as she made Krestel promise to make the Herranis pay for what they did.
It is also known that she is shipping Ronan and Krestel.