Dragons are the tertiary consumers of the underworld ecosystem. It means they eat anything except other dragons, Runeborn monsters, Water Lilies, pure nutrients and Humanoids/Supremanoids/Sublimanoids. Unfortunately, dragons can't move vertically so they are very vulnerable for attacks from up and down. However, the Long Dragons can move up and down too. When a dragon is culled/starved (not killed by heroes), it drops an egg, subject to the amount of nutrients/mana the dragon has accumulated. The egg hatches in 10 seconds and spawns a dragon subject to the egg. For example a Long egg spawns a Long Dragon and a Shin egg spawns a Shin Dragon.
List of Dragons in the games: