At the start of Keeper of the Lost Cities, Biana dislikes and avoids Sophie. Her father, Alden, later makes her become friends with Sophie so that Sophie will go over to their house more often. Biana ends up actually liking Sophie and they become true friends. She often plays Base Quest with Sophie, Keefe, and Fitz.

In Exile, she was depressed after Alden's mind is broken and didn't want to see Sophie after that. She also did not appreciate Sophie coming to Alden's funeral. In the end, she hugs Sophie and apologizes for her actions.

 

In Everblaze she manifests as a Vanisher, like her mom and brother, Alvar.

She goes to join the Black Swan in Book Four and shows that there is more to her than beauty. Biana is very hardcore and has been taught how to defend herself by her parents. She also respects Della as a mother and a role model for Vanishing and aspires to be as good as her someday.

In Lodestar she helps with deciphering codes spends time at the Exillium sessions.

In Nightfall, she is crucial to sneaking them into places because with Sophie's Enhancing she can make several people vanish with her. She also gets severely injured with shards of a mirror when she attempts attacking Vespera and Fintan by herself.