Learning the Demon Way

Rin doesn't know much about being a demon, Amaimon shows up one day and gives his a family present. Something is going to go wrong because he now has something to connect him to Satan and his demonic family and seeds of doubt has been planted in his mind. Who are the 'others? What can they do? What is a mate? What is an alpha? Amaimon is not a child of Satan's, this is not incest.