“You think you're better than me?!? No one is better than me!!”
Morro is a former student of Wu and the former Elemental Master of Wind. He has a cameo in Tournament of Elements, is the main antagonist of Possession and an ally in Day of the Departed and Dragons Rising Season 3.
40 years ago, sometime after Garmadon went to train under Chen, Master Wu met Morro outside his monastery and took him in. He trained him to be a ninja and eventually thought he could possibly hold the title of Green Ninja. When the Golden Weapons of Spinjitzu didn't react, Morro was angered and left Wu. He said that he would find the Tomb of the First Spinjitzu Master to prove he was worthy, but he never returned. Years later, his ghost would return to Ninjago in order to do what he could not in life, and find the Realm Crystal to bring his master, the Preeminent, into Ninjago. His plan would fail, and he would be killed by Nya.
During the Day of the Departed he would return in order to help the Ninja defeat Master Yang, before going back to the Departed Realm.
After the Merge, the Departed Realm and Cursed Realm merged together, and all of its inhabitants "moved on" to a higher plane of existence, or eternal rest. Now the Spectral Lands, departed souls pass through here before moving on, and to honor Master Wu, who he regrets betraying, remains in the Spectral Lands to defend the departed from those who threaten them from moving on.
He is the former Elemental Master of Wind and a master of Airjitzu.