At 8 years old, Lucy is the fifth-youngest child of the Loud family, and the oldest of Lincoln's five younger sisters. Her most annoying habit is popping up and scaring people, which is a running gag in the series. Along with Lincoln, she's the quietest out of all the Loud siblings.
Lucy is a gloomy, cynical, deadpan, and mysterious goth girl, who is almost always sporting a stoic frown. She is interested in occultism, poetry, and the works of Gothic authors, like Edgar Allen Poe and Lovecraft. She has an uncanny ability to seemingly teleport to different places, which often spooks her siblings, especially Lincoln. Some of her siblings refer her as a "spooky" girl. She frequently uses words to describe her actions, such as saying the word "Sigh" instead of actually sighing. The reason for her gloomy and miserable persona is because she feels left out that nobody listens to her and everyone thinks she's weird (despite their obvious quirks).
Though typically rather gloomy, she is shown to be happy on several occasions. She squeals and laughs in "Heavy Meddle", along with her sisters, after knowing about Lincoln's romantic situation. Also in some other episodes she can be seen smiling from time to time (as opposed to her usual smirking), like in "It's a Loud, Loud, Loud, Loud, House", where she is joyfully celebrating the money finding with her other siblings, and in "In Tents Debate", where she is happy that she gets the option to go to "Aloha Beach". She is also shown to be rather compassionate, as she shows sympathy for Lincoln's dilemmas, and always shows her appreciation for his kindness.
In "Sleuth or Consequences", it is revealed that she was responsible for clogging the toilet with her book Princess Pony, stating that even she needs "a break from the darkness" once in a while. Despite her depressed and cold attitude, she looks to enjoy being with her siblings, and sometimes depart from darkness to have fun with them.
"Lucy Loud loves all things spooky and dark. She can usually be found reciting her moody poetry, or sharing her morbid point of view. If you haven't seen Lucy in a while, don't worry...she has a knack of mysteriously appearing when you least expect it!".
Lucy has very pale, almost chalk-white skin, and her long black hair conceals her eyes. She's very thin, and a bit smaller than Lincoln. Lucy dresses in black and white, and she wears long striped arm sleeves, matching knee socks, a black dress worn over a striped shirt, and black shoes.
Her nightwear is a white t-shirt and striped pants. Her swimwear consists of a striped swimming dress, with black leggings.
In the alternate dimension where the sisters are boys, Lucy's counterpart is a male goth named Lars. Like Lucy, he shares the same room with Lynn, but also shares with Lincoln (as Lincoln's original bedroom is still a closet), and instead of a bed, he sleeps in a coffin. Unlike Lucy however, Lars is disrespectful towards Lincoln, obnoxious and agressive, as shown when the latter accidentally scratches his coffin bed after getting a rude awakening.
Eight of Spades
In the minicomic Deuces Wild!, Lucy interprets the superheroine called The Eight of Spades, who is also one of Ace Savvy's sidekicks. She uses a shovel with a spade shaped head. In the comic, she is summoned by Savvy (played by Lincoln) alongside the rest of Savvy's deck (played by the rest of her sisters) to help him and One-Eyed Jack (played by Clyde) to defeat the gas monster. After they defeat it, they prepared to fight against a garbage monster.
The Eight of Spades made another appearance in the comic Lincoln wrote in "Pulp Friction". In this appearance, she dug a hole in which two thugs were thrown into by The Night Club's music.
She is the quietest of the Loud siblings, along with Lincoln.
Lucy and Lincoln are the only siblings shown as babies on screen.
Her winter outfit and costume of "Eight of Spades" make her resemble Raven from Teen Titans.
Along with Leni and Lana, their names mean something related to light.
She has a pet bat named Fangs, which makes her the third Loud sibling after Lana and Luan to have her own pet.
In "Spell It Out", it's revealed that they go on nightly walks together.
Lucy's favorite food is blood pudding.
When Lucy grows up, she wants to be an "undertaker by day, vampire by night".
Lucy and Lola aren't close to each other, like how Lynn and Lana are.
The main reason could be because even though it's revealed by Lincoln in "Room with a Feud", that Lucy and Lola both have a flare for the dramatic, Lucy is gothic, gloomy, spooky, dark, moody, depressed, cynical, deadpan, mysterious, and dislikes the color pink, whereas Lola is girly, spoiled, arrogant, conceited, bratty, sassy, smart-mouthed, prim and perfect, and dislikes ghosts, thus making them both too different to be close to each other.
In addition, there hasn't been an episode were Lucy and Lola are shown getting along with each other. It could be possible it happens in a future episode, but for right now, we're not going to get that.