Daisyie

so this manga has the protaganist of this dude who is a professional hitman and killing people in general. After his hitman session, they gather and the boss says they are going to stop killing people for one year and the guy agrees. He then has to live as a normal person without killing people or anyone finding his identity. He hides as a older brother to his coworker (as you may say so) which is sister to him. Please help me find it. <333

so like this manga, has this dad and he kills his daughter's boyfriend. His wife finds out and they help each other hide it from their daughter and the crime scene. His dad writes bad mystery novels in his spare time and reads them. Please help me find it. <333