What is a subdimension

Subgenre is a multiple index of unknowns, more commonly referred to as dimensions or separate spaces.

The term "dimension" in Japanese ACGN works usually refers to the fantasy world of the work and its various elements. For example, a world in which the rules and order are completely different from those of the reader's existing world, such as a world in which magic or steel bullets exist, is often referred to as an "interdimensional world" or simply "interdimensional".

Additionally, virtual characters traditionally represented in print media, such as manga or anime, are often referred to as "secondary characters" because of their two-dimensional nature, which is actually less time-dimensional, as opposed to real-life (three-dimensional, also less time-dimensional) characters. However, characters created with three-dimensional computer graphics are called "2.5-dimensional characters" because they are in the virtual world and have the concept of three-dimensionality.

Three-dimensional dolls, etc., are physically defined as third-dimensional, but are sometimes called "2.5-dimensional characters" because they are often based on the three-dimensionality of second-dimensional characters, or because they emphasize their virtual nature

Based on the above etymology, virtual characters that only appear in ACGNs are called "2.5-dimensional characters.

Based on this etymology, those who are only interested in the virtual characters that appear in ACGNs, but have no interest in the opposite sex in reality, are jokingly referred to as "residents of the secondary world", and in severe cases, are jokingly referred to as "second dimension withdrawal syndrome".