She is Kazuya's childhood friend in the Beelzebub franchise.
Azusa Fujisaki is Kazuya's childhood friend, yet she does not want Kazuya to introduce her like that to new people such Aoi Kunieda.
According to Aoi, she has a bubbly personality and can say her feelings without hesitation. Azusa easily finds out Aoi's crush is Oga, but she keeps Aoi's crush a secret. She loves cute stuff like the magical girl outfits in episode 27.
In the manga, Azusa did not dress as a magical girl or a maid. Whereas in the anime, she dress up as a magical girl to help Angelica to find Yopel, and she dress up as a maid because she wants to be in the maid cafe.