The level of reality that the setting takes place in. When comparing two realities, the external reality is the one that contains the internal reality within it. For example, Base Reality is external to Contained AI Environments. It is adjacent to many other realities, which are noticeable when finding an Existence Atoms compared to the other normal atoms which contain their own realities. Some planes are in fact from temporarily tangled realities/atoms. Base Reality is both external and internal to itself, leading to the Recursive Existence.