It's easy bro, What you need to do is shoot the acoylte's eye's that appear and who ever shoots them get's a buff towards ogre's that does serious damage, As soon as ogre is dead you need to go on the platform and deal as much damage as you can to the witch, try killing if you can ( swords are really good ) If you can't kill her the 1st time you need to kill the ogre that appears again by shooting the eyes and getting the buff then kill the witch.