Dramatical Murder Temporada 1 Episódio 12

As Rens memories pour inside Aobas mind, Aoba uses Scrap on himself in order to speak with him. Aoba sees that Ren is falling apart due to the worm. Ren reveals he was originally a part of Aobas consciousness, his restraint that was created to monitor his desire (the other Aoba) so that it wouldnt take control of him. However, there was a period of time when Aobas desire took hold of him and Ren could no longer influence him from inside his mind, prompting him to transfer his consciousness into the Allmates dog body when Aoba discovered it. As a physical being, Ren was able to influence Aoba more easily, but because of Virus and Trip tampering with Aobas memory in the past, Ren had forgotten his original purpose until the worm infected him.