There are a large number of universes that, for various reasons, are not Looping. In most cases, this is because the Admins have not brought the universe online yet, either because it is not yet needed for fixing Yggdrasil, because it is damaged and needs further attention before it becomes viable, or because there are complications the Admins have not yet solved. However, in some cases there are universes that are either impossible to get running in the time-loop environment or which would be dangerous to the stability of Yggdrasil as a whole. Such universes are marked as Read-Only, or in some cases completely quarantined from the rest of Yggdrasil.

Universes that are not yet activeEdit

The majority of worlds that might Loop are in this category, and an exhaustive list would be impossible. Some examples are (listed by their Hub backups):

  • The works of Shakespeare, on account of nobody having actually written a Loop in any of these settings.
  • The Mask
  • Etc.

Read-Only universesEdit

These universes are either unstable enough to not be able to Loop properly, or more often involve concepts which are incompatible with the Loops, such as especially complex time travel or multiverse travel. Loops may still occur in these universes, but there aren't any native Loopers or Anchors. Furthermore, removing or reverse-engineering technology, magic, or the like from these universes is verboten, generally enforced by Admins assigning lots of boring paperwork. Some Read-Only universes are:

  • Once Upon a Time (for now): The multiverse travel made this Loop impractical until recently. Although it has been figured out how to handle this complication, no Loops have actually happened yet due to complexity.
  • Sliders: The interdimensional travel device used in this Loop was unstable before the Loops began, offering little to no control of its "Slide" destination. The number of dimensions visited is more numerous than possibly even those included in Once Upon a Time.
  • Primeval: The fact this universe is filled with holes that cross the time-space continuum makes any sort of crossover this series could ever have undoable. 
  • The Movie- Lucy: The drug that exists in the universe has the capability of giving the user the ability to control minds, control matter, shapeshift, master any weapon or language within minutes or even seconds, control electronics, access every memory they've ever had, use telepathy, obtain mind reading, and travel through time. If that wasn't a big enough no no, once the user reaches 100% mental capacity they undergo apotheosis, and become all of existence itself. It is unsuitable for looping. 

The problems that force Read-Only universes to be Read-Only may be addressed in the future, but this is difficult and should only be attempted with care.

Formerly Read-Only Edit

These are universes that were not Looping, either unable to or weren't needed, until they were activated in one way or another.

  • Terminator: Until Twilight Sparkle successfully advanced SkyNet to the point of being able to Loop, there were no viable Anchors. Due to the dangers SkyNet originally posed, this Loop was marked Read-Only.
  • Doctor Who: Once the Admin Zurvan applied a upgraded Nesting Doll Protocol with a Jörmungandr upgrade on an Ouroboros Patch, locked down any time travel enabling tech, decreased out of Loop capacity on tech such as Sonic devices, and locked down a few Loop aware beings and races, the Whoniverse finally came online, with The Doctor as its Anchor.
  • Rockman / Megaman: The complexity of the timeline, and its multiple branching paths even in baseline, created a demonstrably unstable loop where the system was incapable of finding a viable Anchor. Hephaestus' attempts to force an Anchor to activate, in conjunction with a number of other concerns -- and the work of one or more malicious entities -- resulted in the event known as The Crash. Since then, the loop has been active with Rock and Roll as co-Anchors, albeit in a manner which has Hephaestus biting his nails to the quick on a regular basis.

Quarantined universesEdit

These universes have contents, constants and/or rules which pose a significant threat to any visiting Looper or to Yggdrasil itself. This could be due to either containing a potential MLE, or being so unstable that certain events happening during the Loops would likely lead to further harm to Yggdrasil. They are isolated from the rest of Yggdrasil and are not allowed to Loop. The most famous examples are:

  • Uzumaki. This universe has heavy viral infection, posing a psychological danger to anybody in the universe. When quarantine was somehow breached and Simon, the anchor of Gurenn Lagann, Looped in, he was corrupted, and this corruption was almost permanent. Further complicating matters, this corruption is particularly dangerous to beings with Spiral Energy, with includes anyone that has visited Gurenn Lagann.
  • Saya no Uta: This universe includes many destabilizing elements, especially psychological trauma; some 'stable' Loop variants include the release of biological contaminants that turn entire populations into eldritch abominations. The possibility of a virus of this nature getting into a Looper's Pocket is too tangible a threat to ignore.

Formerly QuarantinedEdit

These universes used to contain content or rules that could be harmful to Yggdrasil, (and visiting loopers), but were eventually sorted out by the Admins. So far, there is only one example.

  • Homestuck. So far the only example of a previously Quarantined universe, this universe used to be highly unstable, due to the fact that it had privileges that were only supposed be given to Yggdrasil's Skaia Protocol. It began Looping when Ganesha made it so that Yggdrasil distinguished between Homestuck's Skaia Protocol and Yggdrasil's Skaia Protocol, thus removing Homestuck's special privileges.

Stable Edit

These universes are not Looping, simply because they are were not destabilized enough by the event that started the Loops to need Loopers.

  • Eiken: The only Universe besides the Hub to remain unscathed by the Event that started the Loops, it is run by the Greek Goddess Aphrodite and is her only universe because she is, quote, 'allergic to hard work.' Because this branch is completely stable, it locks down every non-native ability, including subspace pockets: for this, and several non-PG reasons which need not be enumerated here, it's considered a punishment loop by all but the most perverse or idiotic of Loopers.
  • Ah! My Goddess: As that is the universe that Yggdrasil itself is in, instead of running on Yggdrasil. Keiichi Morisato is awake and helps the resident Admins, Urd, Skuld, and his girlfriend Belldandy, run a service loop, but does not Loop out of Ah! My Goddess.
  • The Hub: The "Trunk" Of Yggdrasil, contains back up data for all universes in Yggdrasil, Looping, Non-Looping, Read-only, Quarantined, and Stable, as well as being the universe we inhabit, it has been called Yggdrasil's Anchor.
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