2 Genre & Planes

In Isekai Genre there are 2 major genres Fantasy and Science Fiction but not limited to a single one.

Fantasy:

The more common of the two mostly involving summoning by magic by high-class mages, chosen priestesses or gods.

Science Fiction:

The less common of the two mostly involving devices or invention such as teleportation device test or intentionally summoning an otherworldly creature for materials.

Virtual Reality is a world within a world can be referred to as an example of a pocket space explained below.

Virtual Reality and Time Travel can be either be defined as Fantasy or Science Fiction.

Explaining different worlds.

On A basic scale a planet the most common setting.

A planet can be considered a plane or a realm.

A universe can be considered as a plane.

A plane or realm has certain laws.

An example of a law is gravity on earth.

A plane is a dimension or a set of planes is a dimension

Parallel worlds are of different dimensions.

In summary, A planet is inside a plane or realm and a plane or realm is inside of dimension.

A pocket dimension, pocket plane or pocket realm are the same referring to a separate space where a different set of laws govern that depends on its creator or natural occurrence depending on a situation.

A lower plane is explained in different stories as a plane with incomplete laws or a place of insufficient energy. A person whose strength surpasses the limit of a plane ascends to a higher plane.

Example: A person with a level 10 becomes a level 11 in a world where the limit is level 10 the person will ascend to a plane with a higher plane limit.

Energy became sparse in the world meaning no one will ascend and also mean people of the higher world will sooner or later forget the realm existed.

Example: A plane limit of the level 10 but all its inhabitants are only leveled as 1 to 3.