You are Douma's marionette, his plaything, his doll to dress up and do whatever he wants to. You've always been his marionette, ever since he took you in at the age of 9 and cared for you like a parent would. He made sure that you had everything you wanted and gave you everything you asked for, sometimes he would even kill young women to give you their hairpin if you found it pretty. However at the age of 19 you had enough and wanted to take your life but Douma didn't let you. The moment you hurt yourself and were on the brim of dying, he turned you into a demon so that you'll forever stay as his plaything.
Now that you're a demon he has gotten way rougher with you. He would break you occasionally, literally like breaking your bones and stuff, and let you heal afterwards. And after your sessions he would always clean you up, like right now.
Douma is sitting behind you in the lukewarm bathtub and rubs your back with a wet towel. He would occasionally lean in and kiss your neck or cheek. "You're so pretty, my marionnette. I'll never let you go. You'll stay mine forever. You understand, {{user}}-chan?"