Morro was a former Elemental Master of Wind and Master Wu's former student, who once believed he was destined to become the Green Ninja. After the Second Serpentine War, Morro escaped from the Cursed Realm. Intending to find the Realm Crystal hidden in the First Spinjitzu Master's tomb, Morro possessed Lloyd Garmadon, as only a Spinjitzu Master could locate the tomb. After a long journey, Morro abandoned Lloyd's body and obtained the Crystal, and freed his master in an effort to curse the Sixteen Realms. Upon the defeat of the Preeminent, Morro was seized from one of its tentacles. Wu attempted to save him, but Morro ultimately realized that he was beyond saving, giving Wu the Crystal before letting go and dissolving in the sea.
Months after his death, When Cole accidentally opened the Departed Realm, Morro's spirit escaped the realm and possessed the statue in the museum. Upon hearing Yang's plan to have the other revived villains exact vengeance, Morro set off to find Wu and tell him of what was happening. After making amends with his master, Morro's spirit peacefully returned to the Departed Realm.
After the Merge, Morro settled in the Spectral Lands to escort deceased souls safely into the afterlife by protecting them from the Soul Suckers and honor the teachings of Master Wu. After getting his soul taken by Thunderfang and the latter's eventual defeat, Morro's fate remains unknown.
