IMPT!
I actually made it to the final stage without realizing I can move the arrows UP and DOWN!!
Manage to beat the last boss after knowing that...
1. Move arrows up down according to his position.
2. Spam hobbits to slow him.
3. Make sure you get 9999 mana before destroying their castle.
4. Spam Angels. (Dragons as well if you have surplus mana)
5. Press and hold down "A,S,D,F" to shoot continuous arrows.
6. Buy the slow down and turret upgrades.
 "Kingdom of The Wind")
 "Epic war")