Persephone Jackson (better known as Percy) is the daughter of Percy Jackson and Annabeth Chase. She grew up with her grandparents (Paul and Sally) and had no idea about her connection to the gods until Posiedon shows up and takes Percy away to his palace because her parents are missing.
She goes by her father's name because according to her "Persephone is too long, and most people don't even pronounce it right. Gramma Sally shortened it to Percy before I had any idea that that was my dad's name."
Finding Percy and Annabeth:
Though an unoficcial quest, 12 year old Percy is kidnapped by her grandfather Posiedon and asked to find her parents. After taking Percy to Camp Half-Blood to explain things to Chiron, she picks two new friends Lily DiAngelo (daughter of Nico DiAngelo) and Stella-Mae Grace (daughter of Thalia Grace) they go on a search for the parents Percy'd never met.
Percy is much like both of her parents, she can be strict, but she'd do anything for her friends. She is very smart, and the best swimmer at Camp Half-Blood
Percy has her mother's blonde, curly hair and her father's green eyes. Her face is dotted with freckles, and has dimples whenever she smiles.