The Ultra Dragon is a four headed dragon in Ninjago. It is the new form of the four dragons after they molted together. He is also Lloyd Garmadon's dragon.
The Ultra Dragon's master is Lloyd Garmadon. At first, he had a difficult time riding the Ultra Dragon, but soon got the hang of it. the dragon arrived to save the ninja just in time and battled The Great Devourer and seemed to have the upper hand, forcing the Devourer into retreat before being smashed to the ground by the Devourer's tail from underneath. Lloyd Garmadon rode it in Ninjaball Run but lost after Kruncha and Nuckal pulled the Ultra Dragon out of the race using a skeleton arm on the Skull Truck. It took the Ninja home from the Island of Darkness and held Sensei Wu, Misako, and Dr. Julien on it's back during the final Battle between Lloyd Garmadon and The Overlord. The Ultra Dragon is last seen with Lloyd and the other ninja after the Overlord's demise.
The Ultra Dragon is the most powerful out of the Ninjago dragons so far just like his master Lloyd Garmadon being the most powerful out of the ninjas. The Ultra Dragon naturally has the powers of all four elemental dragons. Each elemental head shoots a powerful breath of energy of it's own respective element except for the earth elemental head (Rocky). Below are the powers of each head:
Fire-Shoots a powerful blaze of fire.
Lightning-Shoots powerful bolts of lightning.
Ice-Shoots a freezing wave of ice.
Earth-Increases striking rate.
All the Ultra Dragon's powers were shown when it fought the Great Devourer. Also the Ultra Dragon is not struck down easily. This is shown when it recovers to help the ninjas after being struck by the Great Devourer's tail and helping Lloyd reclaim the Bounty after the Skull Truck pulled him and Lloyd down in the Ninjaball Run.