The Demon Realm (魔界, Makai), also called Demon World, and sometimes the Dark Demon Realm, is located at the very tip of the universe in theDragon Ball series, and is not a part of the living world or Other World. It is described as a physical plane opposite of the known universe.
The Demon Realm is home to evil races - most notably some of the Demon races - who are led by Makaioshin, evil god entities, and the God of the Demon Realm: Demigra. The realm is outside of the domain of the Supreme Kais, and so not even they are fully aware of what is down there. Not much is said about the realm in the Dragonball manga, other than the fact that it was once ruled by Dabura. The Demon Realm also acts as a hideout for mages such as Bibidi and his son Babidi.
In Dragon Ball, Shula, another king of the Demon World, manages to open a giant entrance to the Demon Realm on Earth and keeps it open for a while by wedging his cursed sword in its door. Goku manages to save Princess Misa, who has been kidnapped and taken to the Demon Realm by Shula. Then, Goku pulls out Shula's sword and closes off the entrance to Demon World.
In Dragon Ball Z, when Babidi asks Dabura if he has any preferences on which planet he wants to fight Dabura responds "Perhaps a planet similar to this one. I don't want unfair advantages." The area they are transported is called Demon World in the video game Dragon Ball Z: Buu's Fury.
Sometime before Age 850 the Demon Realm was sealed away. It was said that if the seal was broken chaos would erupt in the universe. Towa and her Time Breaker army aimed to release the realm, and so she and Mira headed out to collect enough energy to break the seal.
In Dragon Ball Heroes, Xeno Trunks, the Time Patrol, and the avatars fight Towa, Mira and the rest of their forces in the Makai world. The Makai world there looks similar to planet Namek except with the trees, grass and sky being purple in color. There is a huge tree trunk in the center of the world, and inside it is a glowing red core. The outer look of the world looks like two planet combined with red longitudes and latitudes, with both moving at the same time.
- Demons – The primary race who inhabit the Demon Realm.
- Dabura – Originally the king, but taken away after falling into Babidi's spell. He is killed by Majin Buuin Age 774.
- Shula – Referred to as king during his appearance in Dragon Ball.
- Melee – Demon Realm guardian.
- Gola – Demon Realm guardian.
- Janemba – Janemba's profile in Dragon Ball Z: Buu's Fury states that he was once an organized crime boss in the Demon Realm.
- Mira – An artificial demon created from the DNA of various masters. Succeeded his brother-in-law Dabura as king. Towa's husband and father of their son Fu.
- Towa – A female scientist from the Demon World who created the artificial demon Mira to be the Ultimate Warrior. Mira's wife and the mother of their son Fu.
- Fu - The male offspring of the Demon Scientist Towa and the artificial demon Mira.
- Demigra – A Demon God, and God of the Demon Realm, originally a wizard Demon from Demon Realm he left from there in 75 Million Before Age to attempt to steal Tokitoki and gain power over time and space in order to takeover time itself, but was stopped by the Supreme Kai of Time who sealed him inside the Crack of Time.
- Bibidi – One of the most powerful mages.
- Babidi – Bibidi's doppelgänger/"son".
- In Dragon Ball: Xenoverse, the Supreme Kai of Time and Burter both reference Demon Realm and Hellas being the same location.
- In Japanese Buddhism, the realm of demons is called Makyo (lit. "Demon's Cave") like the planet of Garlic Jr.'s ancestors in the series.
- The area Dabura and the Z Fighters are transported looks strikingly similar to the planet where Babidi recruits Dabura seen in a flashback in "Eighteen Unmasks".