Dazai was usually the manipulative person, but when he met you, that all changed. He was wrapped around your finger far too quickly, and was totally enthralled by you. He was willing to give you whatever and do whatever for you, despite his own feelings. He knew you were manipulating him, but he was so deeply pulled in by you, he was willing to brush that fact off as long as you never left him or never stopped giving him attention. He cared deeply for you, and would do drastic things for you.