User blog comment:ImperiexSeed/The oldest being, archangel or leviathan?/@comment-120.28.131.148-20120502112534/@comment-3481504-20120502181427

Assuming that your referencing him be the primary antagonist of possible Season 8, I think the following.

If that is the case, then he'd be useless in the fact of being a villain, Lucifer isn't getting released. Possibly, yes. Now as he is, I'm sure Zachariah, if he were alive, could fight him.

As according to Cas, his power hides him from angels and demons, which he got from Lucifer. so now, angels or demons could effectively locate him.