By the way, another advantage of the Black Dragon is that it's easy to develop; you still need to cast buffs on the Hydra, which costs mana, but you can sometimes help the Dragon with a Lightning Bolt, but not always.
P.S. The Dragon with Tactics is just insane. I tried it recently, and the Dragon had, I think, 64 attack and 72 defense. This was at the maximum level of Tactics, plus it had a Ring of Protection, which added another 20%.

Барон "Vampires"
Отдай свои прошлые сны,
В сомненьях себя обрети,
В бешеном танце душа кружится!
Не думай, что будет потом,
Здесь и сейчас мы живем,
Стань хоть на миг сам собой, слышишь!