Yeah, this whole thing makes me imagine a VERY BAD scenario, where Sin is left alone, or with someone more "submissive" in the backseat (I can't find a better word); and just proceeds to kill someone, alter or human, without telling any others, or making the backseating alter keep the secret too. He certantly seems like he has the capacity to, I really do hope that never happens, it'd be terrible, and I hope you've got some way of stopping that.