Voted Heroes III Crystal Dragon. This awesome unit is one of the best neutral units of the entire game. There's a backround story for these creatures inruduced in The Dragon Slayer campaign (H3: AB). We learn that the Crystal Dragons were a personal invention of the Wizard Dracon's mother, who is an excellent academian and a trainer of young Wizards.
The powerful beasts are half mechanical and half living Dragons thus making them able to be Resurrected. The undocumented fact concerning the Crystal Dragons is that they have 20% chance of resisting enemy magic. (similar to say, for example, the Dwarves) Their special ability, crystal production, means that the player receives a certain amount of crystal each week based on the number of Crystal Dragons in his/hers army.
Let the stats of the unit speak for itself.
Health: 800
Speed: 16
Attack: 40
Defense: 40
Damage: 60-75
Not a bad deal for 20K gold and 10 crystals!
Yurian
Don't worry if things are going badly today. They will be much worse tomorrow.