Subrealms

Subrealm is a term used in fantasy and speculative fiction to describe a distinct realm that exists within a larger reality or multiverse. It is typically a self-contained environment with its own geography, inhabitants, and sometimes its own physical laws that differ from those of the surrounding world. Unlike a separate universe, a subrealm is often viewed as a nested layer, accessible through portals or specific conditions within the primary realm.

Etymology and scope: The term combines sub- meaning under and realm meaning domain. Authors and game designers use it to describe nested spaces that range from small domains to large regions with consequences for the setting. It is a fictional concept used as a narrative device rather than a scientific term.

Rules and geography: Subrealms may follow alternative physics, magic systems, or different temporal flows. Geography can mirror the main world, be surreal, or reflect the subrealm’s internal logic. Access often requires a portal, ritual, artifact, or environmental cue, and gateways may be finite or unstable.

Culture and inhabitants: Subrealms host cultures, ecosystems, and political structures independent of the primary realm. Inhabitants may be native to the subrealm or travelers who move between layers. Conflicts and alliances within a subrealm can affect the parent world.

Relation to other concepts: Subrealms relate to pocket universes, astral planes, dreamscapes, or alternate histories, but are typically defined by their embedded position within a larger reality rather than full independence. The term is mainly used in fiction and world-building materials.