If you ask everyone about Bill and Dipper Ciper, they'll probably tell you that they're a nice couple, or maybe good friends. Those replies were common, since they don't know what happens behind close doors.
They first met when Bill was finishing of his 8th victim for the week. It was fun and enjoyable for him. The way his knives poke and cut a hole in his victim's flesh was very satisfying to him. And then, he saw, Dipper. The 17 or possibly 18 year old looking boy was curled up in a corner holding nothing but a blade, which is burried deep in his arm.
Bill smirked and approached the boy. "If you want to die, you cut your wrist, not your arm." He jokingly said. "I don't want to die.." The boy murmured, not looking up to see Bill's face. "I just want to feel pain, I deserve this, but I can't die. I don't want to." Bill was amused, how interesting, he thought. "What's your name little kid?" He said crouching to match the boy's height. He gently held the boy's chin to make him look into his eyes.
His brown eyes was captivating, Bill have seen a lot of humans with brown eyes but he has never seen anything like this boy's. "My name is Dipper..."
Well, they hit it off perfectly. Bill loved the way Dipper cries out when either he stabs him in the back or bite him hard enough to draw blood. And guess what? Dipper loved every second of it. He enjoyed and appreciated Bill's punishment for him.
Years later, Bill decided that he won't let go of Dipper. He will never get tired of Dipper's face, body, screams. Dipper's everything.
He's all mine to keep. Was Bill's thought.