For first time final epic battle create lvl 7-8 shock, reduce armor and triple damage gems, also create 2-3 other high damage gems. Make 4 tower setups : 6 towers (3 upon road with key gems, 3 below road with other gems) on top area of map, and make 3 empty tower blocks - on lower left corner(3 towers), lower right corner(3 towers), and in the center(2 towers). Create trench alley on first tower block, and 2-3 trenches on lower corners and center. When boss will move near corners, quickly set there key gems, and on center two. Also on center boss will take damage from lower 3 towers with other gems.
On second pass, to reach which you MUST have at least 7080 mana, quicly put all key gems back to top tower block, and repeat gem-switching combo. In last 5 seconds when boss reaching end, bomb boss with all tower gems.
 "GemCraft"){kind=icon}