i was thinking the volcano could be the defense building, watch'a think? It would have the same power as the lava drake, but can't move.
Vassal : Hp 250, no attacks, workers abilities, worker speed.
Fire drake : Same attributes as drake rider in magic? Will have a flame attack, no ep.
Earth drake : I dunno about this one, please post ideas!
Sky drake : Shoots lightning, has 1200 ep, can do an extreme lightning attack, deals 200 damage and consumes 20 ep. Normal attack deals 150 damage. Very fast on his feet. Hp should be 3000
Lava drake : Lava attack, very powerful, but no ep attacks. Damage is 500 with a 3 splash radius. hp should be 1000. Not very fast.