Sadako is the leader of Sophie's fan club. She devotes her time to protecting Sophie.
Sadako has long layered dirty blonde hair and bangs with blue eyes. She wears a pink headband with an "S" on it over her bangs. She is typically seen in the Sophie's Fan Club jacket with her school uniform.
She goes to Paprika Private Academy.
It is quite possible she may be an active Idol or simply goes to PriPara in order to keep her duties as the leader of Sophie's Fan Club.
(Source: Pri Para Wiki)