Valhalla Knights

Secrets: Monster becomes Super strong
Beat the game and at the end of the credits, you will have a choice to save.
Save and load your game. Go to the entrance of the prison and talk to the
guard. He will ask if your a true adventurer. Select the first option and
the monster will becomes stronger than normal. Talk to the guard again
and select the 2nd option to return the monsters to normal.

 