You said earlier that you don't have access to multiverses anymore, if you aren't in one right now, where are you instead?
Universes: AUs, non-AUs, and cores
AUs: Alternate universes, born from creators. They contain their own timelines* as well as their voids*.
Timelines: Diverging paths of events in a given AU (eg. Pacifist, neutral, genocide runs; continuity changes such as Horrotale or Dusttale) these can be manipulated within a given AU by a being with powerful enough DT.
Void: The empty space within an AU, once entered leaving is nigh impossible (eg. Gaster; Color!Sans; Seraphim!Sans.)
Non-AUs: Outcode spaces, created by outcodes, either through code manipulation or overtaking of an already existing AU.
Membranes: That which seperates universes and multiverses from antivoid*, membranes can be passed through by certain individuals or with tools. (eg. Guardians; Errors; outcodes; //categories only applicable within Multiverses//.)
Cores: Root universe, from which all AUs stem from or passageway for guardians of creativity (Doodle spheres) depending on the Multiverse
Antivoid: The empty space between universes. Hostile to all incodes and most outcodes. Has effects on beings code that can lead to them becoming errors.
Antivoid (Multiversal scale): The full space between multiverses, hostile to all beings.