Introduction: Worlds and Travelers

Worlds

The different universes that can be found in the multiverse are called Worlds. The primary division among these is whether they remain intact or have suffered a collpase and the subsequent fragmentation. Those that have splintered into fragments are known as Shards, while those that remain whole are termed Old Worlds or Realms. Another category would be Dead Worlds, utterly consumed by the Maelstrom.

Old Worlds

Realms are not exposed to the tumultuous forces of the Maelstrom and thus have not been shattered. They have two very distinct parts: the World itself and the encompassing stability bubble. The stability bubble is part of the fabric of the multiverse but is still not affected by the Maelstrom shielding them from collapse but also isolating them from the rest of the multiverse. Accessing or escaping a Real is almost impossible and this isolation gives them unique sets of laws of physical and magical laws. Unlike Shards which are finite, Realms stretch to infinity in size.

Stable Realms

Stable Realms are surrounded by a robust stability bubble and thus are immune to any kind of natural collapse. Typically consequences of the actions of a very powerful being that usually but not always is infinite in power. While this barrier makes their reality the most difficult to traverse, the same entity that isolates it can consciously permit travel if it aligns with their intentions.

Metastable Realms

Metastable Realms lack an entity capable of shielding it, it has a natural resistance to the Maelstrom. While they are in most cases destined for an eventual collapse, they can endure for billions of years, providing the illusion of a Stable Realm. Some of them are completely devoid of life and thus earn the name of Dead-like worlds. Their stability bubble is thinner, but thick enough to prevent multiversal travel.

Shards

Shards are remnants of shattered universes, small fragments that have survived the calamity. In place of a stability bubble, they are surrounded by a pseudo-reality bubble that shields them from the Maelstrom but at the same time permit multiversal travel. Unlike their isolated counterparts, they share most laws of physics and magic even if there are apparent differences caused by local conditions, like for example in a Shard magic would appear unexistent because of the lack of native observable magical phenomena or native magic users. Pseudo-reality bubbles also enable the Shard to host life as it generates the surroundings from the little information remaining on the Shard. For example, if the Shard is a single island, it may have days and seasons despite having no actual sun and its inhabitant will see the sea around it and even other islands despite not being able to interact with them. Such pseudo-reality though is lacking in detail and can be inaccurate: for example, the stars might not move around and seasons lack any kind of variation between years.

Classification through habitability

Shards can be classified according to their habitability. Some can be habitable just fine and are called Live Shards but others can have problems. Shards unable to sustain life (or simply unsuitable to most life forms and devoid of them) are called Dead Shards, while Shards on the brink of becoming uninhabitable are called Dying Shards. Worlds that would be called Dead Shards but are inhabited by some form of life (often elementals, undead and other species capable of surviving anywhere) are called Inhospitable Worlds.

Classification through size

Size serves as another criterion for Shard classification. Most fall into the Island Shard category (2 to 50.000 square km) but smaller ones called Microshards and larger ones called Continental Shards are possible. Some rare shards, Planet Shards, are larger than even Continental shards and encompass entire planets or even solar systems. Some Microshards can be used to construct vessels able to navigate the Maelstrom, such vessels are called Ark-shards as some artifacts are capable of moving castle-sized Shards even inside other Shards.

Classification through multiplicity

The majority of Shards are Monoshards, composed of a coherent single remnant of a single world. On the other hand, there are Shards that are in fact composed of the collision of disparate Shards and are thus called Bishards, Trishards, or Polyshards. A Monoshard can still exhibit several planes of existence, but as long as they originate from the same universe they do not qualify as a Polyshard.

Travelers

A lot of people ventured into the Maelstrom to other worlds, such users are called Travelers. A phenomenon that facilitates their travels is called Multiversal Translation. As long as two languages are considered equivalent (For example English in a UK-based shard and latin in a Roman one or two different "dragon languages" of different worlds) their speakers can understand each other (or if the speaker consciously wants it, the other person will directly hear their own language). Equivalency is considered from the perspective of the respective Shards where the languages were acquired. For example, latin would only be the lingua franca equivalent if it is the lingua franca of the shard where the user learned latin.

Isekai

Isekai is a very special kind of Traveler, unlike Travels who travel in their native bodies Isekai is formed by the multiverse when they abandon their native shards (Although, from that point on, they are like any other traveler). They come from either Dead or Old Worlds and most of them are reincarnations of dead people although there is a variant called copies that are actually replicates of living beings in Realms. A very small percentage of people become Isekais although, the incomplete nature of a dead person makes them usually merge with other versions of themselves in the multiverse making a single Isekai more than one person.