The Realm of the Mind is a plane of existence created through magic and technology. It can only be entered into by leaving one's body behind and traveled through with one's mind, hence the name. It is expressed in different ways: an empty red void, the Bloody Moon, and the Bottomless Land, however it is simply the core of The Cradle, through which it calculates and prompts the transmission of magic to beings inside The Cradle who ask for it. The trasmission is done by data transmission pipes known as keys, which are made up of magic power who is materialized as information. This allows lifeforms to possess the ability to control large amounts of magic power in an extremely short period of time, so as to shorten the time needed for their growth.
Often compared to an ocean of numerous stream of minds, it can pose some danger to its visitors, since some of them sink to the bottom, leaving the slightest trace behind them while others floated off with the tidal waves. The difference between the two lay whether minds had consciousness. That was what parted higher minds from lower ones. The ones sinking to the bottom were useless, to the demons, whereas the floating ones indicated that they had entered the Realm of Mind before.
According to Lan, there were various rules that governed the Realm of Mind, so much so that even God might not be able to change those rules at will.  This can be explained by the limited adaptation that God had after magic entered the universe after Project Gateway and the way the The Cradle was set up.
In it, territories can be established and further developed, such as the Dream World, the Presiding Holy See, the Divine Domain, Scroll's file room and Hackzord's realm. These realms appear to only exist, however, while its creator is connected to the Realm of Mind, and as such disappear for others inside it or near it in the Realm of Mind.
According to the Demon Civilization, although the Origin of Magic was where all kinds of power stemmed from, what everything returned to, and also what created the Realm of Minds, it would destroy everything coming near it before its upgrade. When diving in it Hackzord described a burning and chaotic sensation. The burning sensation resulted from the Origin of Magic. As for the chaotic feeling, it came from minds themselves. Once magic power reached a certain point, it would leave marks on a person's mind. It is often associated by Demons with the Origin of Magic, however, it later is revealed that magic originated from the rift created by Project Gateway. 
- Diving in the Realm of Mind can be dangerous, Demons said that some lost themselves in it. Silent Disaster, for example, said that some Witches who confronted her in the Divine Land drowned in the Realm of Mind.
- Chapter 1489
- Chapter 1089
- Chapter 1223-1225
- Chapter 1488
- Chapter 1089
- Chapter 1413