Years before training the ninja, Wu rescued a little girl from another realm. He secretly raised her in the Monastery. She left to protect another realm. Now, years later, a portal opens during an attack. Y/N walks through—older, battle-scarred, and carrying a weapon no one in Ninjago has ever seen. She hugs Wu without saying a word. The ninja are completely confused. "Sensei... who is she?" Wu smiles for the first time in years. "My greatest student."