User blog comment:EmpyreanSmoke/Supernatural Q&A/@comment-27457157-20150912042207/@comment-24834479-20150912233042

No, archangels do not have access to Purgatory, so they wouldnt be able to send Leviathan back there. Leviathan are physcially stronger than archangels, becuase they are much older, and are physical beings. I would say that Castiel was willing to fight Dick, becuase he has been inside of him, and he knows him very well.