There are many different strategies that you can use for a no loss run. But in my opinion, it just makes the game boring. There are many other creatures that effective to use or at least funny to play like sea dogs, assassins, necromancers... Forget about no loss and enjoy the game. If you feel the game is too easy even in impossible, feel free to increase enemy's strength up to 300% and you will definitely know when to stop trying no loss medal
