Ninjago: Day of the Departed

Day of the Departed is a television special of the computer-animated television series Ninjago: Masters of Spinjitzu (titled Ninjago from the eleventh season onward). The series was created by Michael Hegner and Tommy Andreasen. The special aired on 29 October 2016 to coincide with Halloween and follows the sixth season titled Skybound. It is succeeded by the seventh season, titled Hands of Time. 

Day Of The Departed

On the Day of the Departed, Cole realizes his ghostly form is fading away, so he goes to Yang's Temple, but accidentally opens a passage to the Departed Realm, reviving the Ninja's old enemies (Samukai, Pythor, Kozu, Cryptor, Chen, and Morro) via mannequins in the Hall of Villainy. Yang orders the villains to go after the Ninja and curse them to take their place in the Departed Realm. Cole finds that Yang is trying to resurrect himself using the Rift of Return. Morro, instead of fighting Wu, warns him of Yang's plan. The Ninja defeat their adversaries, reunite and set off to Yang's temple. Yang tells Cole he wanted to be immortal so he wouldn't be forgotten, but Cole assures Yang he'll be remembered as the creator of Airjitzu. Cole crosses through the rift and becomes a human once more, but the rift almost closes the moment he crosses through it, giving him a ghostly green scar on his face.