Satoka lives in Nagasaki, on the southern island of Kyūshū. She is very well off, having a limo, butler, and a private jet, but states she's not that rich. She wears Satoru's hat and seems to always be with her. Unlike Touko's mask, she takes it off when needed. Satoka is still new to the Yume Tsukai, so she is receiving lessons from Rinko, who blasts at her to call her sempai.

Spoiler

Shy and timid Satoka joined the Yume Tsukai after her boyfriend, Satoru, another Yume Tsukai, was killed. She still carries the burden of his death, but later on finds the strength to carry on the title of Doyousei.

(Source: Wikipedia)