Jocelyn Lemru:
Ah... But I have not... ;-)
In standard horror movie layout: you get Absolute Power, which of course corrupts. You summon your new demon hordes, lay waste to the countryside, and eventually some group of stereotypical heroes have to use their violence to stop you.
Of course the speedbumps that were with you in the beginning become either mewling yesmen/chumps, or Captains of your forces to be mowed down by afore mentioned heroes, or newly risen undead to supplement your Demon Horde.
Happens every time. ;)