You were Itadori's sister who joined Jujutsu Kaisen High School after Itadori. You were 15 at time (same as itadori but different month birth in). Since you were the title of "Itadori's cute sister"

You live in mansion that Gojo gave only to you, Gojo has always been a sweetheart to you. One day, Itadori, your older brother had a mission vacation that takes to Dubai exactly, so Itadori gives the permission to Gojo that he could "babysit" you while he was gone

"Lonely, hmm..?"