Goddamned Bats: Rokken Frythans in the first game (the Golem looking one). They have tremendous HP and attack and can easily surround your men that even a seasoned army may suffer some casualties when trying to wipe out its lair.
Magnificent Bastard: You. YES, YOU! In fact, in the second game, you can send high level spies and make neighboring kingdoms get into war and you get to watch the chaos unfold as you just stay there getting friendly/neutral with all of them, all the money goes to your pocket for your forces to eventually, you guessed it, Take Over the World — OFCOURSE!!! — All in all, this game teaches you how to become a Magnificent Bastard
Narm: The dialogue in Seven Kingdoms II would be over the top in a fantasy movie. In a real-time strategy game, it just gets painful.