User blog comment:Twilight Despair 5/Oldest Enemy or Species./@comment-3481504-20120511180043/@comment-3045936-20120512075624

As confirmed in the series, interviews, and Salutes to Supernatural for season 7 with Jensen, Jared, Misha, and even the actor whom portarys Death says that Levianthans are the oldest known species in the series. Being far order than the Angelic race. Also Death said Long before God created Angel and Man, which means like mankind the collectively whole of the species. And while, Archangels are older and more powerful than lessar Angels they are still angels. So when he meant Angel he meant off al Angelkind.

And this is my take on the subject. God, and Death first whether before or at the moment of creation as in the series Lore. But after than the around similar timeframes beings like the most anicent pagan deities, other Horsemen, and possibly reapers came to exist. Then God after the creation of the universe itself made the Levianthans. Long after sealing them away, he created the Archangels, and lessar Angels, Seraphs, regular angels, cherubs etc.