Choosing the wrong species

I purchased a lizard army of 8 archers, I researched enhanced woodworking and archery to give archers +2 damage and +3 speed. I reinforced the castle walls by +200. I even trained a lizard hero and erected a battle flag. Yet within mere seconds of the cragon (cat dragon) attack, I lost almost half of the army and my castle was on fire. I'm starting to think that felines are overpowered...