Monkey King: Enma (猿猴王・猿魔, Enkōō: Enma) was the personal summon of Hiruzen Sarutobi, the Third Hokage.
In the anime, during Hiruzen's time as the teacher of the Sannin, Enma was summoned during their training sessions.
At some point in time when Hiruzen went to accost Orochimaru who had fallen under suspicion, Enma was summoned after Hiruzen decided to confront him. During the confrontation however, Hiruzen allowed Orochimaru to escape despite Enma's appeal to kill him.
During the Nine-Tailed Demon Fox's attack on Konoha, he fought alongside Hiruzen against the beast.He and Hiruzen also later witnessed the Nine-Tails being sealed inside of Naruto Uzumaki.
Hiruzen summoned Enma during his battle with Orochimaru, to help combat the reincarnated Hashirama and Tobirama Senju when the former had used his Wood Release Secret Technique: Nativity of a World of Trees technique in an attempt to crush Hiruzen. Enma quickly formed a lattice around Hiruzen, protecting him from the attack. With a transformed Enma in hand, Hiruzen was able to hold his own until he realised that his reincarnated opponents were indestructible as the battle waged on. Given no choice but to use the Dead Demon Consuming Seal to seal away his predecessors' souls at the cost of his own, Hiruzen attempts to do the same with Orochimaru so he would never harm Konoha again. However, while attempted to seal Orochimaru's soul, Orochimaru tried to plunge his Kusanagi sword through Hiruzen's chest, but a restricted Enma was able to grab onto the sword and prevent it from killing him until Hiruzen had sealed Orochimaru's arms. With the deed done, Enma pulled out the sword before vanishing, noting that Hiruzen had died as both a true shinobi, and a great Hokage.
When the Ten-Tails transformed into its tree form, a reincarnated Hiruzen summoned Enma who transformed into his staff form to help him free Naruto Uzumaki. Enma, alongside Hiruzen and the Hokage, later watched on as a transformed Naruto and Sasuke launched another assault on Obito. Later, while the tree is stopped by Orochimaru'ssnakes, Hiruzen wielded Enma in his staff form to destroy the tree's branches.
- Enma is one of ten summoned animals that wear a forehead protector suggesting that his loyalty is strictly to Konoha. The others are the Ningame of Might Guy and the eight ninken of Kakashi Hatake.
- When Enma vanishes after Hiruzen dies, he takes Orochimaru's Sword of Kusanagi with him; it is unknown how Orochimaru retrieved it.
- Enma is a caricature of the legendary Chinese Monkey King, Sun Wukong. Sun Wukong carries a staff which grows and shrinks at will and wears the pelt of a legendary tiger as well.
- In Buddhism, Enma is one of the twelve Deva. He's chief judge in the afterlife, when a person dies they must appear before Enma (and also before other judges), who decides whether the person is good or bad; the person is then sent to the most appropriate afterworld. Among the judges of hell, Enma is the most important.