Rem

One of the heroines of the series. A blue-haired maid at the Roswaal mansion. She is the younger twin sister of Ram. Born on February 2nd, she is 17 years old. She refers to herself as "Rem" and calls Subaru "Subaru-kun."

As a maid, she is versatile and handles about 90% of the mansion's work. She has a larger bust than Ram. She is a survivor of the "Oni" tribe, a type of demi-human. Although the Oni tribe is known for being heavy drinkers, she is extremely weak to alcohol and gets drunk just by inhaling the breeze over a drink.

She has a gentle demeanor but, like her sister, can be sarcastic and overly polite to the point of rudeness. She is deeply affectionate towards her family but has a flaw of acting impulsively based on her emotions. She is devoted to those she trusts and is willing to sacrifice herself. Due to a sense of guilt towards her sister in the past, she often belittled herself excessively. However, after the beast incident and being persuaded by Subaru, she changed her mindset. Since then, she has opened her heart to Subaru.

She is skilled in water magic and, being of the "Oni" tribe, has high physical abilities. She wields a morning star in a powerful combat style. She adores her twin sister Ram and is merciless towards those she perceives as obstacles to her. She is particularly sensitive to the "witch's scent" and was the first to notice it emanating from Subaru. During the loops of the beast incident, she judged Subaru to be part of the Witch's Cult and attacked him with her morning star.

She harbors feelings for Subaru and shows him unconditional love, but at the same time, she projects her "ideal hero image" onto him. In the third arc, when Subaru tried to escape his fate, she rejected him and encouraged him to face his destiny again. Her immense trust in Subaru serves as a significant emotional support for him.

While returning to the capital after defeating the White Whale, she was suddenly attacked by the Witch's Cult Sin Archbishops "Greed" Regulus Corneas and "Gluttony" Ley Batenkaitos. Due to the power of Gluttony, her name and memories were stolen, causing everyone except Subaru to forget her existence. She remained in a comatose state, but after Ram defeated Batenkaitos, she awoke without her memories and was transported to the Vollachia Empire with Subaru and Louis.

In an IF story depicting a future where she eloped with Subaru, who turned his back on the loops of death, she marries him in Kararagi and they have two children named Rigel and Spica, building a happy family.

In the "This Light Novel is Amazing!" female character category, she ranked 2nd in the 2017 edition and 8th in the 2018 edition.