From the handbook (Page 37):
Built by: Acolyte
This enormous dragon is Aramon’s most powerful unit; only one of which can exist at one time however. With three levels of fire attacks, great range and hit points by the cartload, Gold Dragons are magnificent killers.
It has fire breath, homing fireball, and after getting 30 kills, it gains the ability to use an earthquake attack. Its first two attacks get stronger as it gets more kills, and it gains greater hit points and heals faster too.