Mairu, unlike her sister Kururi is a troublemaker at school like her brother Izaya.She  introduces herself as liking to read encyclopedias, manga, and adult magazines. She also declares that she is bisexual and is looking for girls who are interested. Like her sister, she is a big fan of Shizuo's brother Kasuka. She stated that she would gladly see her brother be ran over by a truck to be able to see Kasuka. She is very good at martial arts and is what you would say is that she's more hyper than her sister. She tends to kiss her sister somewhat often.