Rosalie appears as a teenage girl with medium-length strawberry blonde hair in a bob cut and light green eyes. She typically wears a billowy purple dress styled with sailor-collar features, twin rose-colored stripes, and a black neckerchief, along with a matching purple beret adorned with a fuchsia bow. Her attire can change for special occasions through a spell Azusa created.

Rosalie’s tragic past shaped her into an initially rude and abrasive individual, speaking a corrupted form of the local dialect and often scaring people. She admits that “years of being dead have made me a bit… cheeky.” After her liberation by Azusa, her demeanor softened, becoming more considerate and welcoming, though traces of her former harshness remain.

Rosalie was the daughter of a wealthy merchant in Nascúte. Known for her grace, her life took a tragic turn when her father’s business failed and he tried to sell her to the Red-Light District under the guise of marriage to a nobleman. Upon discovering the deception, she took her own life by hanging. Her strong attachment to the material world kept her spirit tethered to the site of her death, where she became a foul-mouthed, territorial ghost. She haunted the land until Halkara built the Nutri-Spirit factory, but locals refused to work on haunted ground. With Azusa and Beelzebub’s help, Rosalie was freed and now resides peacefully at the House of the Highlands.