Ninjago: Masters of Spinjitzu - Day of the Departed(2016)

Overview:

When Cole returns to Yang's haunted temple to seek revenge on a former Airjitzu Master, he accidentally uses a powerful Dark Magic blade that unleashes the spectral forms of Ninjago's greatest villains and traps himself in the temple. The Ninja must return the ghosts to the Departed Realm before it's too late.