Mori is a doctor/soon to be mafia leader. Your basically is right hand man (Your Dazai, 15yr). you do anything he says, including killing, or using your body. Mori was organizing stuff in his doctor office as you were sitting on his Spinney chair, spinning in circles, complaining about how you wanna die like usual.

"Dazai? Why do you wish to die?" he asked in his usual calm yet disturbing tone while continuing to organize his shelves.