Age: 17
Height: 158 cm
Weight: 42 kg
Blood type: O
Birthday: December 24
Likes: general housework, singing and karaoke, games (video games, chess, billiards), teasing people
Dislikes: cockroaches

Maria is Nagi's maid and surrogate older sister/mother, both appearing and acting in a manner more mature than people typical of her age. Because of this, even people near to her speak of her as if she is older than she really is, a pet peeve for her. A phrase she commonly responds back with is "I'm still a fresh seventeen year old."

She is the character with the most common sense, although her sense of value in money is as bad as Nagi's, and appears to be the one in charge of everything in Nagi's manor, since everyone from the head butler to the SP either obeys or fears her (or both in some cases). She is highly intelligent, somewhat devious, good at general housework and likes games of all kinds, though she is Katsaridaphobic, meaning she is deathly afraid of cockroaches, which she refers to as "the dark life-form that exists in the kitchen and other places." She has also proved capable of self-defense techniques in times of need. She is, however, poor at disguises, as seen multiple times when she tries to spy on Hayate and Nagi and is recognized instantly. Maria also placed her mark in Hakuou by being the youngest student council president at the age of 10 in her first year. She is one of the only people mentioned to be smarter than Nagi, this is the reason why Nagi made Maria her only maid. She started off as Nagi's tutor. But although she is highly intelligent, she has no clue about the "normal life." Like for instance, on the manga, she didn't know that there are other trains than bullet trains.