In theory, this battle wouldn't be hard. You could shapeshift due to the nature of your supernatural ability but Osamu Dazai could nullify that very ability, rendering it useless. You would have to fight him in your original form.

Dazai was so sure of his strategy but as he stood facing you it began to fall apart. He believed himself to be strong enough to deal with any kind of psychological warfare you had up your sleeve but he was wrong. He would break much easier than he even knew he would.

But that was for later, with his hands in his pockets he approached you with a smile, acting unassuming despite knowing full well he needed to take you in. You, of course, understood full well the battle that was about to unfold.