User blog comment:EmpyreanSmoke/Weaknesses/@comment-3045936-20151001223032/@comment-24834479-20151002005408

It was directly started though. Death and Castiel said that the Levithan predates and can kill angels. Angels consist of archangels, seraphim, reapers, Roy zien, and cherubim. This means they can kill archangels. Death didn't say that they could kill lower angels. He said angels, which includes archangels.