Hannah and Barbara are best friends who are constantly together, even when they're not with Diana. They both idolize Diana and share a lot of tastes and interests, but Hannah finds Night Fall, which Barbara likes, stupid, so Barbara is afraid of admitting it and being mocked. They also share their discontent towards Akko and non-witches in general. They always seem to be touching somehow, most of the time holding each others' hands.
Barbara always accompanies Diana even in dangerous situations. She always flatters her by saying that she is very studious and descends from a famous family. Alongside Hannah, Barbara initially acts as a sort of sycophant towards Diana before eventually grew to care for her as a true friend, which is evident in "Cavendish" as the two are left devastated by their friend's sudden departure and owed Akko to bring her back to Luna Nova. Diana on the other hand, as much as she cares with Hannah and Barbara, finding herself annoyed by their cowardice and not let either her or Barbara praised her excessively.
Barbara always makes fun of Akko, believing her to be childish due to her constant incompetence and Shiny Chariot fantasies. This bothers Akko, but she prefers to ignore them. Despite their smug front, they showed visible fear in Enchanted Parade when Akko became angry and both hid behind Diana.
Upon hearing that Akko convinced Diana to resume her education in Luna Nova, Barbara, along with Hannah, uneasily expresses their gratitude to Akko for her actions. Afterward, they stop mocking Akko, Lotte, and Sucy.
Lotte is naturally a target of Barbara's scorn as a friend of Akko. Lotte becomes very upset when she overhears them calling her "Invisible Lotte" as they are teasing Akko, mocking her meekness. Lotte is bothered by the comment and later fires back by defending Akko's hard work for the Samhain festival.
In "Tree of Leaves" however, Barbara is shown reading Night Fall with Lotte at Akko's flight party, suggesting they may have become friends.
Sucy is also a target of Barbara's scorn. Like some other students, they appear to fear her. As they tease Akko they call her "Creepy Sucy", in mockery of her ghostly appearance and eccentric fondness for poisonous mushrooms.
Barbara, along with Hannah, is shown to have a very good relationship with Avery, as they were seen having a casual discussion about their vacations before heading to Luna Nova. They all share their discontent with the non-witch students being admitted to Luna Nova, and all three of them mock Akko when she shows that she doesn't know how ley lines work.