Toujou Household
Mio Naruse[]
Maria is originally given the important task of serving as Mio's guardian. Over the course of the series, the two grow closer and even act very much like sisters. Despite usually being "punished" for her shenanigans by Mio, Maria loves Mio and would sacrifice her own life if that's what it took to protect Mio.
Basara Toujou[]
In the beginning of the series, Maria likes to act as Basara's "wingman" and find ways in order to instigate various lewd shenanigans in order to help him deepen his bonds with the girls that have contracts. Although she tries to tease Basara and play it off as a joke, deep down, Maria really wants to be like the other girls and have the same kind of relationship with him.
Yuki Nonaka[]
Maria shown little close interaction with Yuki, but she has shown to act lewdly towards her as she did with everyone else living in the Toujou Household. However, Maria is more careful toward Yuki than anyone else, especially whenever she tries anything when Yuki is asleep, fearing that she might draw out Sakuya.
Kurumi Nonaka[]
Initially, Maria and Kurumi started off as enemies. But eventually, they become friends.
Celis Reinhartd[]
Moderate Faction
Sheila[]
In the beginning of the series, since Maria wasn't told the true story about her upbringing, she often blamed herself for her mother's appearance. However, after learning the truth, Maria is able to accept herself and reach her full potential. Although Maria knows her mother has her best interests at heart and whenever Sheila visits, Maria often ends up in a lewd situation, causing her to feel uncomfortable.
Lucia[]
Despite Lucia being fairly rigid and uptight, Maria has great respect and love for her older sister. After discovering Lucia's love for Eroge, Maria often reads the posts Lucia makes on the beta forum as a way to grow closer to her.