Responses
Actually, it is hinted that Sin is David or has major characteristics of David when Hakuryuu "killed" his mother and then she possessed his sister. But thinking about it... it is possible that the sister was only a option for Arba once she had died ( you know like Valt in Harry Potter (?))
Anyway, Arba had called Sin her king and father and that she would love to be besides him. So yup...
Does this remind anyone else of Solomon and David