The Daimyo first appeared to recover his son, the Ultimate Ninja, after the Ninja engaged Leonardo in a duel to the death. Following this, the Turtles met him upon their first visit to the Battle Nexus. His history with Master Splinter was briefly talked about, as he saved Miyamoto Usagi and Splinter from an attack by Drako. The Daimyo was excited that Splinter's sons had joined the Battle Nexus Championship, and he decreed that they be allowed to enter despite being improperly registered. However, this led to Drako seeking revenge and possession of the War Staff. The Daimyo, summoned by his son, was wounded by Drako's assassins. After being saved from a second attack by Usagi and Donatello, the Daimyo was forced to watch as his son and Drako were pulled into a warp caused by Drako's use of the War Staff. He closed it, and was left to grieve, after crowning Michelangelo as Battle Nexus Champion.
Some time later, when Leonardo came to the Nexus seeking his time-scattered family, he found the Daimyo weak and not thinking clearly. Ultimate Drako, the fusion of Drako and the Ultimate Ninja, had weakened him and were planning to destroy him. However, the Ninja could not hurt his father, and the Daimyo's spirits remained broken after his son died. Lord Simultaneous noticed him grieving and the Daimyo's son was returned to him as a young boy, much to his joy.
The Daimyo later judged Michelangelo's rematch with Kluh. He sensed the interference of the Levram wizard who removed the Battle Nexus anti-fatality spells, but could not intervene due to the Levrams taking his son hostage. After the Ultimate Ninja was rescued by Leo, the Daimyo took the Levrams prisoner.
The Daimyo appears in the game Teenage Mutant Ninja Turtles 2: Battle Nexus.
- The word "daimyo" is pronounced like "dime yoh" /daɪmjoʊ/, but the show mispronounced it "dah mee yoh" /dɑːmijoʊ/, as if spelt "damiyo."