The Hydraking is an evil Monster that roamed the Seas during the Spinjitzu Wars. He is the Demon of Water and Poison. He has three heads, like a Hydra.
it was revealed that he created the Great Devouer during the Great Spinjitzu Wars against the Overlord and the real one responsible for Garmadon's Possessed Evil.
- He has the Powers of Water Tsunamis and Poison Powers.
- He uses his heads as weapons.