Rem has medium length sky blue hair that covers her right eye, large light blue eyes, and young features. She also has hair clips towards left side of her hair, flower-shaped ribbon on the same side of her hair, and a maid hairband. She looks nearly identical to her sister apart from her hair, eyes, and ribbon coloring.
Ram has medium length pink hair that covers her left eye, large red eyes, and young features. She is nearly identical to her younger sister except that her eyes slant upward slightly and has a smaller chest. She usually wears a maid uniform which she wears neatly.
She usually wears a maid uniform, and since her chest is slightly larger than her sister’s, she secretly changes the measurements to hide it.
Rem tends to speak in a superficially polite manner and sometimes acts without thinking. She holds both respect to the point of worship and guilt toward her sister for an incident in the past.
Because of her respect and guilt toward her sister, she used to think of herself as inferior. After Subaru saves her, she falls deeply in love with him, becoming one of his most loyal followers. Rem will stick with him no matter what happens, even if Subaru rejects himself.
Currently Rem has had her name and memories eaten by Ley Batenkaitos, erasing her existence from the world and putting her in suspended animation.
Rems abilities include:
Water Magic: Rem is skilled at Water Magic and Roswaal estimates her skill as being in the lower high. She is able to attack and heal using her magic.
Equipment: Rem wields a Morningstar in combat.
Oni Bloodline (鬼の血族 Oni no Ketsuzoku): As she is an Oni, Rem can enter her Oni Form, manifesting a single white horn on her forehead. The horn increases her physical abilities and acts as a gate which gathers mana from the atmosphere.
The cut and design of maid uniforms vary giving a designer a lot of artistic licenses to emphasize the elements of the uniform, such how cute or sexy it is, which is important in anime. You can see the variety in maid uniforms with characters like Tohru (Miss Kobayashi’s Dragon Maid), Faris Nyannyan (Steins;Gate), and Nekopara’s Chocola and Vanilla.
Ram is seemingly self-centered and does things at her own pace, however in actuality she maintains a distance from people to ascertain them. She believes that Roswaal is the greatest and no one else is as precious except for her sister Rem. She is slightly more outgoing in comparison to the generally taciturn Rem, who generally allows Ram to take the lead in their sisterly bond.