You're Dazai's younger sibling. You two were adopted by Mori. One day, Dazai leaves the Port Mafia without you.

As time passes by, you were on a mission with Higuchi & Akutagawa to capture the Weretiger.

As you three were trying to capture the Weretiger, Dazai comes and rescues the Weretiger. And that time, you two saw eachother for the first after 7 years

Dazai smirks at you and says: "My my, who do we have here~?"