Master Wu is the wise, ancient mentor of the ninja and the Master of Creation. He is the First Spinjitzu Master's second-born son, Garmadon's younger brother, Misako's brother-in-law, and Lloyd's paternal uncle. Wu grew up learning the art of the ninja alongside his older brother, Garmadon, who was infected with evil. They fought together as a team against evil for countless years, until Garmadon was fully corrupted and he was subsequently banished to the Underworld. Around a decade later, Wu trained a group of teenagers in the ways of Spinjitzu so they could protect the land his father created. Wu guided the ninja in many battles against his brother, the Serpentine, and the Overlord. When the Nindroid crisis began, Wu was corrupted into a cyborg but was purified after the Digital Overlord was vanquished. After the ninja went to a mysterious island to save Zane, Wu joined the Elemental Masters to fight Chen and his Anacondrai Cultists. After Garmadon was banished to the Cursed Realm and the close of the Second Serpentine War, Wu's first pupil, Morro, escaped the Cursed Realm. Wu trained Nya to harness her element, allowing her to destroy Morro's master. Shortly after, Nadakhan ravaged Ninjago and trapped Wu in the Sword of Souls, though these events were undone by Jay's final wish. On the Day of the Departed, Wu was met with a revived Morro, who helped Wu reunite the ninja during Yang's scheming. Wu later confronted Acronix, who struck him with the Forward Time Blade that caused him to rapidly age. Though his health was restored by the Reversal Time Blade, he sacrificed himself in a bid to defeat the Time Twins and was lost in time. The loss of Wu left Lloyd in charge of the ninja, and they made it their goal to find Wu. A year later, he was found turned into a baby due to his exposure to the Reversal Time Blade, and kidnapped by the Sons of Garmadon until he was rescued by Cole. Little Wu was with the original four ninja aboard the Bounty when they were almost crushed by the Colossus, until they used Traveler's Tea to save themselves, ending up in the Realm of Oni and Dragons. Marooned, he grew up again while helping his students to fight Iron Baron and the Dragon Hunters and find a way to return to Ninjago. After Iron Baron's defeat, Wu proves himself worthy to receive the Dragon Armor from the Firstbourne. He became the Dragon Master and used the Firstbourne to get himself and his four students back to Ninjago in time to help Lloyd, Nya, and those left behind to end Garmadon's rule and take down the Colossus. Sometime after the battle, he returns to his normal age and reclaims his place as the ninja's teacher. Sometime after, he was present in the arrival of the Oni. He aided his brother and students in performing the Tornado of Creation to vanquish the Oni. Months after battling the Oni, Wu's past comes back to haunt him yet again when the ninja inadvertently released the Serpentine sorceress, Aspheera, who knew Wu as the Treacherous Deceiver, from her thousands-year imprisonment. Once Zane is banished to the Never-Realm after saving Wu from a blast from Aspheera's staff, Wu's attempt to go after him alone is thwarted by the ninja, and he is left behind with P.I.X.A.L. in Ninjago. They attempted to go after them by using Traveler's Tea, but inadvertently release the Preeminent from the Departed Realm. P.I.X.A.L. was able to defeat it in battle and send it back. Soon after, he reunited with them, including Zane. Wu eventually aided Zane and P.I.X.A.L in finding Milton Dyer while the ninja sought Unagami inside Prime Empire. With Jay and Dyer successfully converting Unagami, Wu was able to reunite with the previously cubed ninja, resurrected along with all the other inhabitants of Prime Empire. After the ninja freed the trapped gamers, Wu started to feel left out and think that the ninja no longer needed him. He was then forced by Misako to accompany the ninja to the Kingdom of Shintaro. Adventuring with Cole, Vania, and the Upply, Wu rediscovers his role as mentor when he encourages Cole to never give up when things seem hopeless. After Cole defeats the Skull Sorcerer, Wu is reinvigorated and steers the Destiny's Bounty in search of he and the ninja's next adventure. He travelled with Misako and Clutch Powers' group to the Island of the Keepers but was captured by the Keepers. He was later rescued by the ninja. Later, he would send the ninja down to see the energy pulse that has been disrupting Nya's powers. He asked Kai and Ray to stay to study masters of Fire. He is warned by Cole that the Storm Amulet had been stolen. He, Cole, Kai, Ray and Misako confronted Clutch Powers only to meet Kalmaar and his crew attempt to stop Kalmaar from leaving with the amulet, only to fail as Kalmaar awakens Wojira and Wu witnesses as Nya merged with the sea. He later fights Maaray Guards as Jay battles Kalmaar, he is disappointed by Nya leaving the team and speaks in the memorial. He then spent an entire year trying to find a way to turn Nya back to normal, but refused to take part in the Ninja's plan to free Aspheera. When they broke her out and were subsequently arrested by the New Ninja as a result once Nya was purified by Aspheera removing her powers, Wu's close relationship with the team became strained and he even went as far as to estrange himself from them. In addition, he refused to accept Nya's insistence that she was to blame for their incarceration before inspiring her to become Samurai X again. However, he later realized that he should have followed his own conscience instead of following the law. Thus, he decided to help the ninja again, even if it means becoming a fugitive as well. Once they rescue Lloyd from a resurrected Harumi, learning the Overlord is back and unsure about fighting back, Wu and Lloyd follow some clues, which led to them reuniting with Garmadon and discovering Lloyd's Oni form can turn the tide of the battle. During which, Wu attempted to battle the Overlord, but was ultimately defeated before being rescued by Nelson and Antonia, whom take him to the newspaper warehouse, where he takes leadership of their resistance and proclaims everyone honorary Ninja. Learning from Misako of Dragon Form, Wu observes Kai, Jay, Cole and Zane achieve it at the cost of their powers, and help Lloyd, Garmadon and a redeemed Harumi defeat the Overlord. Afterwards, Wu oversaw the Ninja and the citizens of Ninjago City rebuild the monastery. Sometime later, Wu somehow had a share of responsibility in the Merge, and was missing after this cataclysmic event in which all the realms become one. Wu reappeared as a spirit called Sprite and played a guiding role for his students. He guided Kai and Nya to portal gates leading to the Monastery of Imperium, led Cole on a journey and tried to get Jay to regain his memories. Eventually making his way to the Monastery of Gates, Wu called to Cole, along with Arin, to head towards the monastery which contained the Dragon Ivory Crowns of Horns. It was there that Wu admitted to have been responsible for the Merge before seemingly splitting into four small orbs that each went to different Portal Gates. After the Forbidden Five, Ras and Arin left and got separated across the Merged Lands, he appeared to Lloyd one last time.