Innate Domain

An Innate Domain (に), normally referred to simply as a Domain (に), is an area created in the user's mind that can be manifested using cursed energy. They are normally realized utilizing Domain Expansion, a barrier technique that manifests the domain by constructing an area that traps the user's target inside.

Description
A domain is a metaphysical territory that exists within its creator's mind.

Sukuna's soul is able to exist independently within Yuji's body by residing within his Innate Domain. He said to think of it as if they were existing within his heart.

Domains can only be manifested using large amounts of cursed energy. Doing so can change entire areas into the user's domain. However, domains created with pure cursed energy without a barrier technique or an innate technique imbued are considered to be unfinished. Powerful curses with high cursed energy without proper control over cursed techniques, such as Finger Bearer's tend to generate domains like this.

Some domains expanded with cursed energy can also be concealed by barriers. However, it's impossible to continuously expand a domain empowered with an innate technique. Domains protected by a barrier that exists continuously are also considered incomplete.

Domain Expansion

 * Main Aritcle: Domain Expansion

Domain Expansion is a barrier technique that constructs a real tangible environment using cursed energy that reflects the user's Innate Domain. Unlike unfinished Domains not constructed with a barrier technique or imbued with the user's innate technique, proper Domain Expansions increase the user's techniques and makes it so they cannot miss.

Sukuna's Malevolent Shrine is the only Domain Expansion that does not create a separate space by erecting a barrier.