Maria is Saki's best friend and a beautiful girl with pale, white skin and blazing red hair. She's very strong willed, and commands the weak, quiet Mamoru, but in times of need she devotes herself to protecting him. On the other hand, she does show a girlish fear of scary stories too.

Later, she starts dating Saki.
In chapter 21, it is revealed that she had a child with Mamoru 10 years ago, later they were killed by Yakomaru.
(Source: Crunchyroll)