Who is Sophie?

Sophie is Will's sister and sort-of diving coach. She has a job at Rikki's (formerly Juicenet) cafe.

she's will's younger sister. She's manipulative and cunning. She's also possesive of her brother and wants him to have no 'girl distractions'. She doesn't like anyone at all. She's bossy as heck.
She's much like シャルロット, シャーロット in a way