Scarlet Valentine is a slim woman with long dark hair kept tied into a ponytail with several rings. She wears a dark bodysuit partially quilted on the legs and bearing several crown symbols on the arms. Over that bodysuit, Scarlet wears a short sleeveless dress with a multi-layered heart motif on the chest.
Scarlet is a strong and ambitious woman. She is not shy, having no trouble talking about her husband even when she is seducing a woman, and often takes the initiative. Scarlet follows her impulses when in a relationship. She is bisexual, as she shows affection towards her husband, but also desires intimate contact with women. One of her fetishes seems to be facesitting.
Scarlet's personality also has a violent side. As soon as she discovers Lucy Steel trying to infiltrate her husband's bedroom, Scarlet draws a gun without hesitation and tries to kill her, insulting her profusely as she shoots the girl. Moreover, Scarlet seems to become sadistic when pushed, as she declares that she will have Lucy tortured for daring to use her, and also stirs a nail driven in Lucy's leg to make her suffer.
Fifteen years prior to the story, Scarlet met Funny Valentine at a house party in her hometown. The two danced together, which is when she discovered he could walk without making footsteps and play Mozart on mandolin with his feet. Coupled with this, she fell in love with his sharp, but warm-hearted personality.
Steel Ball Run
Scarlet finds her husband in Chicago. While walking in a park, Scarlet sees Lucy Steel, Steven Steel's wife. Lucy is reading "The Sign of Four", the newest installment in the Sherlock Holmes series. Scarlet has just read it and is still enthusiastic about it. Lucy accidentally falls on Scarlet and sneakily pinches her nipples and then licks her neck. Scarlet takes the hint. Believing that Lucy shares her taste for women, Scarlet decides to bring her to the Presidential residence in Chicago so that they get to better know each other.
In the presidential compound, Scarlet has tea with Lucy and explains to Lucy her past with her husband Funny Valentine. However, Scarlet changes subject towards the attractive Lucy. Growing bolder, Scarlet asks Lucy to shout her name and sit on her face, but suddenly falls asleep. In truth, Lucy has tricked Scarlet and put a sleeping agent in her tea. Scarlet wakes up and looks for Lucy, only to find her in the Presidential bedroom. Realizing she is an enemy of the State, Scarlet draws a gun and shoots Lucy, who tackles the First Lady into the bathroom. Scarlet manages to pin Lucy as the guard dogs approach and wiggles one of the nails Tubular Bells has created in Lucy's leg to make her suffer. Scarlet expects the other balloon dogs to attack Lucy and finish her off, but Lucy then sheds her fake skin, misleading the dogs into attacking Scarlet. The nails impale Scarlet in the head, killing her.
- “You have such a cute nose, don't you know? Call me Scarlet... We're friends now... It's fine, right? Come now, Lucy... Call me Scarlet.”
- “I want you to call my name, Lucy. Please... Everyone calls me "First Lady"... Say "Scarlet" loudly, now! I want you to say it like you’re reproaching me...”
- “Ohhh, so good! Good, that's absolutely wonderful!”
- “Mmm~~! That face, the way you're just quietly listening... so, so, so cute! Let me fiddle your nose! Can I play with your lips too? Can I do it with two fingers? Can I play with your cheeks too?”
- “I love the president! But you're the only one who has such wonderfully pinchable features, Lucy!”
- “I want to ask you a favor... I want you to sit on me... Please, I want you to. [...] That's fine now, right? Now, sit... I want you to squish me! On my face Lucy! I want you to squish me with that cute little butt! Ohh, hurry! [...] Squash me! Until I can't breathe anymore! This is exciting me, come now! Hurry! It's time! Squish my face!”
- “Are you all right...? Poor thing... you look so frightened... But... you fucking bitch! I'll blow a hole in that pretty little face, Lucy!”
- “I don't know what you want, but you're a Stand user! You used me to get in here! I was starting to love you... I was going to take you under my wing and let you be with me forever!”
- “Lucy... how dare you do this to me... I’ll make you pay... I’ll make you see what happens if you deceive me... I’m not going to let you off with just an execution... That’s too easy. I’m going to have you just barely hang on, and make you lose everything you have before you die!”
In the light novel JORGE JOESTAR, a version of Scarlet Valentine from an unknown universe appears. The universe of Steel Ball Run is considered the second universe in the novel. Scarlet appears similarly to her second universe counterpart and is still the wife of Funny Valentine.
After performing a verification check, Scarlet informs Funny that the underground facility beneath the Trinity Church in their universe has been long since empty, with no signs of the Saint's Corpse. The doors that can only be opened from the inside were standing open, with no signs of tampering.
After their call, time starts accelerating from Made in Heaven Ultimate Requiem while Funny is on the island of Great Britain. As Scarlet is not affected in America, from her perspective it appeared as if Great Britain suddenly vanished and reappeared. When The Funniest Valentine calls her again, Scarlet panics, asking what is going on in the island. She asks a flurry of detailed questions which The Funniest answers before hanging up.