Mei is Naru Narusgawa's younger sister by adoption.
She looks up to her sister and wants her to come home. At first she tries to set up Keitaro Urashima with Mutsumi Otohime, but then later gives up and brings Naru good news in the Spring Special.
Mei Narusegawa is Naru Narusegawa's younger sister. Naru describes her as her "half-sister" in manga volumes 11 and 14. On the other hand, in the anime, episode 22, Mei said "My father married her mother." This leads some to believe that they are stepsisters, although this is never confirmed. She initially tries to get Keitaro and Mutsumi together in the hopes that Naru would return home if Keitaro were taken. She gives up on this when she and Naru clear up a few family misconceptions. Also, in Love Hina Again, she makes a very brief appearance to help all the Hinata residents about Keitaro and Naru's relationship and help speed it up. She also appears in the last volume of the manga, seen standing off on the side with the rest of the residents of Hinata-sou while Naru is chasing Keitaro down after accidentally grabbing her dress. She also plays a minor role in the Spring Special and Christmas special.
Mei was created for and appears primarily in the Love Hina anime, though she is referred to in at least two places in the manga and is seen in the last chapter of the final volume of the manga. In the anime television series, Mei is voiced by Yuri Shiratori in Japanese and Rebecca Forstadt in English.