Realms

Realms
A realm is a unique world where voyagers seem to be summoned to in order to complete the Room of Swords. Each Realm is different from one another, having their specific biome and architecture with their unique monsters. Each Realm has one Boss, who needs to be defeated in order to come in possession of their Boss Sword, so to open the gateway to the Room of Swords  ; there also are mini-bosses, also called "warden" that give you a special ability once defeated.

As of today, we do not know how Realms are affected by a change of voyage, as we do know from Kodya that there are slight variations in weather, spawning of monsters etc from a voyage to the next, but we also know that the environment can still be affected by things that happened in the last voyage (See : Footprints from the first and 31st chapters), yet the realm is still supposed to be reset as all things should. Further explanation may very likely be given in later chapters. Realms can also be accessed through the Room of Swords, as seen in the next photo (from chap. 69) ; in addition, Realms that have already been completed will display a green symbol above their doorway. Alternatively, uncompleted realms will display a red symbol.

Completing a realm gives free access to it, with the ability to open the Gateway to the RoS anytime as long as in possession of a Boss Sword (whichever one).