Lucy is a pale-skinned girl with a short and slim build. Her eyes are green and her long crimson hair is styled into two thick braids with choppy bangs and a white flower hairpiece on the left side of her head. She also has braces, though not clearly visible in the manga. She has a scar on her right arm that she obtained during her time at the orphanage from a hot iron poker.
When working as a waitress, she is seen waring an apron and a white triangle headpiece.
Due to her poor treatment at the orphanage along with treated as only a pawn by the Guild, she has a very twisted personality. However, outside of this, she comes off as haughty and rude to hide her true character. After her defeat at the hands of Atsushi, it is implied that she has developed feelings for him, as he was one of the few to show his true kindness and concern for her well-being.
The ability, Anne of Abyssal Red (深淵の赤毛のアン, Shin'en no Akage no An?), allows her to create an alternate reality known as "Anne's Room", in which people are imprisoned if they get caught by Anne the Monster while playing hide-and-seek.
- Exit Door: The room contains a door that leads back into the real world. This door is open and anyone can enter it. Once someone exits through this door, all their memories of their time in the room will vanish.
- Prison Door: This door leads to the prison that Lucy keeps all captives in. The door is locked and must be opened with a special key. When Anne catches someone, several giant long hands will reach out of the door and reach across the room to pull the caught person into the room.
- The Prison: The prison room holds Lucy's captives. The held prisoners are unconscious as long as they are inside. It's supposedly impossible to escape through force once you're inside. The hands that reach out are inside the prison room, often holding the prisoners. Detainees can only be freed by opening the door or through Lucy ending the ability.
- The Key: The key that is needed to open the door is extraordinarily hard to use. It morphs the instant someone attempts to use it, and Lucy herself stated that she doesn't know how to use it. The key has yet to be successfully used.
- Anne: Anne is a giant monster with immense strength and speed. Anne hasn't been shown physically harming anyone, only capturing them so far. It is revealed that Lucy can have at least two copies of Anne active at once. The exact properties of Anne have not been revealed.
Lucy grew up in an orphanage where she was treated harshly as she would have to wash dishes all day long with aching hands and wear the same clothes made from patched up leftovers for a year.
She mentions that she was called a "freak" because of her ability, and later on, was taken into the Guild because of her ability.
- Lucy shares her birthday with another Guild member, Mark Twain, on November 30.
- Lucy shares some similarities with Anne from the real-life Lucy Maud Montgomery's novel, Anne of Green Gables:
- Both are orphans who enjoy speaking and dreaming.
- Both have red hair that is tied behind them in pigtails.
- Lucy is the only member of the Guild with a Canadian real-life author counterpart unlike the other Guild members who are all based on American authors.