Devouring Famine, Plague, and War,... ?

Bbk_agp

     Devouring Famine, Plague, and War,  without the previous lines, we don't know whether "devouring" is used as an adjective, or the start of a participial phrase.  "Devouring" seems like an incongruous modifier for "famine." (famine certainly destroys and kills, but it doesn't devour   -   unlike plague and war.)   If it's a participial phrase, we need to know what it refers to  -   i.e., what's doing the devouring.
       
        Each able to undo mankind,
     Death's servile emissaries are; "servile" is an adjective meaning "servant"    /  an "emissary" is someone you send on a mission   /  So death sends the following various servants on missions to perform its work.
      
       Nor to these alone confined,
          He hath at will
       More quaint and subtle ways to kill;
     A smile or kiss, as he will use the art,
     Shall have the cunning skill to break a heart.

Thanks a lot