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.
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. Diana, however, she is bothered that they are very fearful and thinks that they should have an attitude more proper of a witch. In the anime, Diana is indifferent towards them and, if she learned of the "pranks" that Akko performed while under her guise, Diana seemingly left her roommates under the cold of the night.
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 on Akko for her actions. Afterwards, 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 became 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.