Maazu is an ancient hell demon that can shapeshift into any form.
The history of Noodle's hunt for Maazu was told in the 2016's Book of Noodle and The Chronicles of Noodle.
When Noodle opened a giant oyster shell in hopes to find a pearl to give to Chiyoko to repay for her kindness, Noodle released Maazu. Before Noodle set off to find the demon Chiyoko gave her a small, yellow bird named Hato to guide her. Towards the end of Chronicles of Noodle, Noodle heard the sound of laughter and the scent of dried fish on rice, which made her follow the noise which led her to Jinmenju, the all-seeing tree. Not too long after, the fruits with human faces laughed at Noodle, saying she "killed Maazu". Noodle searched for Hato, who was before in her hood's safety, but Hato wasn't there. Noodle thought to herself "The bird was Maazu! Or rather, Maazu was the bird, taking its form to lure me into danger after danger". Noodle walked away from the tree and continued her search. For years, Noodle pursued Mazuu across Japan. Finally, she had tracked it down to Tokyo, where it had risen to the top of the criminal underworld. She infiltrated its headquarters, The Demon's Lounge, while being disguised as a geisha. While Mazuu was distracted, Noodle sliced its head off. Its earthly existence was over.
- In The Book of Noodle the name of the demon is sometimes spelled "Mazuu"