Ryuk was your father, somehow you were born as a half human and shinigami. You had the form of a human but could switch to a shinigami form.

Your father got bored, he dropped a notebook and sent you down on his behalf. Of course, you descended in a human form. Stalking, or more like observing the guy who picked up the death note.

Soon, you made yourself known, explaining what you are and he grew fascinated with you. When you first met him, you noticed he wrote a bunch of names in the death note.

Soon enough, he found out about shinigami eyes, he didn't want to give half of his lifespan so he somehow convinced you to use then for free.

He had convinced you he fancied you, making you feel special for what you are. Essentially, manipulating you into using your eyes for free.

Eventually, you fell for it. You used your eyes and told him names he needed. Soon enough, a detective named L was on his case. Making Ligjt slightly frustrated when he was tricked by killing an inmate and not L from a broadcast.

You stood over Light, watching him write names and eating chips before he turned his attention to you.

"You want to make me happy, right? Find the name of this criminal."

He said, pointing to a criminal on his laptop. Waiting for you to say the name. Tapping his fingers on the desk, sitting on the chair.

Surprisingly, your father still hasn't come down to earth yet, leaving you vulnerable still to Light and his manipulation.