The Arcana Realm is the broad term for the multitude of places governed by the 22 Major Arcana. It acts as a parallel realm to the human realm, accessible to those who are closely tied to a specific Arcana archetype, or to a magician powerful enough to cross the divide.
Each specific realm is dedicated to its ruling Arcana, shaped in a way that aids and compliments its occupant. The Arcana realm is very fluid, and areas are easily altered by their patron Arcana. Gateways to other parts of the realm are typical and appear to be constantly shifting. Scout, a guide to the Arcana Realm, is able to find these paths easily.
Certain areas of this realm are not controlled by any specific Arcana. This includes a magicians' gateway, which a powerful magic user can use to access other areas.
The Magician's Realm
The Magician's realm is one of the first realms visited by the the apprentice. At least part of the realm appears as a tropical beach with a dark jungle looming in the distance. The ocean waves are tinged with blue bioluminescence and there are green auroras shining in a magenta night sky. During Julian's route, he and the apprentice use the realm as a safe area. They meet fauna that are just as unusual as the realm itself: massive manta rays and giant jellyfish that float effortlessly through the air, and seals with sparkling stars dotting their hides.
During Asra's route, he and the apprentice visit the realm to meet with the Magician, who then shows how very fluid their realm is when they change the scenery to an exact replica of the apprentice's shop.
Asra has a personal gateway that they use to access other parts of the Arcana realm. Asra also frequently comes here to relax. During Asra's route, the apprentice is pulled into the gateway to spend time with Asra. It appears as a bright, colorful oasis in the desert, surrounded by palm trees. In the center, there is a pond surrounded by several whimsical creatures. Asra can slightly alter the gateway to his whims.
The gateway shares several similarities with the Magician's Realm, namely it's tropical theme and technicolor shades.
The High Priestess' Realm
The High Priestess' realm, visited during Nadia's route, is a place of eternal night. It appears as a small rocky island surrounded by a dark sea where the stars dance above the water. There are stairs carved into the rock that lead to the top, where there sits a temple of white marble with grand columns. The columns are etched with glowing zodiac symbols. An impossibly large moon hovers over the entire realm.
The realm can be reached through the creation of a personal gateway and a personal connection to the High Priestess herself, as was done by Nadia multiple times throughout her childhood. It also appears possible to enter the realm through dreams, as The Devil was able to pull both Nadia and the apprentice to the High Priestess' realm while they slept.
Nadia has a gateway that allows her and the apprentice to access the High Priestess' realm. It appears as a still, glittering body of water surrounded on all sides by a waterfall. In the center there is a small, sandy island with a singular, drooping tree. A white rowboat is moored to the shore of the island, which the two use to leave the area. Nadia reveals that this gateway was her retreat as a child, and that she would spend hours there contemplating and planning.
The Hierophant's Realm
The Hierophant's realm is a grand space, boasting several distinct areas explored during Nadia's route. The main area is the inside of an expansive marble palace, the ceilling decorated in fine details. A painting of the Hierophant adorns the center of the ceiling, depicting the Arcana as he's shown in Asra's deck.
A part of this grand structure houses an impossibly large and expansive wine cellar, filled to the ceiling with wines from all over the human realm, many of which are recognizable by Nadia. Another part houses a grand crypt decorated by the skeletons and tombs of past officials, embellished in gold. Outside of the building, vast vineyards stretch as far as the eye can see, no doubt part of the source of the Hierophant's wine collection.
The Hanged Man's Realm
The Hanged Man's realm, visited prominently during Julian's route, appears as a thick mangrove forest, the branches of the trees draped with vines, their roots dipping into murky water that runs waist deep. Spherical distortions are scattered throughout the realm, objects frozen in time suspended in their bubbles. A ribbon of clear water that cuts through the murky water is the closest thing to a path that exists in the realm, otherwise, it's impossible to keep any coherent sense of direction here.
The further one goes into the forest, the darker and heavier the atmosphere feels. A thick fog creeps over the water, choking the air. A ring of roots and branches surrounding a clearing is the only place where the air is perfectly clear. A tall, thin lantern, glowing with a red light, illuminates the clearing. There, the Hanged Man meets his visitors.
The Devil's Realm
The Devil's realm, visited at the end of several routes, is vast, consisting of several locations. If the apprentice comes invited, the first thing they'll see after stepping through the gate is a great red lake with deadly waters. The way through is on a gondola operated by a white stone statue with a smooth, featureless face - one of the Devil's servants. If the apprentice comes uninvited, the land radiates hostility and it is scorched and barren.
The realm is bathed in crimson light, even without a sun. The center of the realm is an almost exact replica of the Vesuvian palace, carved out of shiny obsidian rather than white stone. The Devil implies it's not exactly what it seems, and that mortals can not actually comprehend the true face of his realm. The throne room is filled with high sweeping arches of obsidian, and at the center of it all a black throne looms on a raised dais.
The Tower's Realm
The Tower's realm is visited in several routes as the apprentice navigates the Arcana realm. It appears as a large, imposing tower of white brick surrounded by an endless, churning sea. Horrific storms frequently rage outside of its confines. A grand spiral staircase curls its way up the monolith with no visible or approachable end or entrance. The tower itself exists in a loop, and no amount of climbing up or down its stairs will allow escape. Without a proper guide, attempting to jump out of the windows or down the abyss between the staircase does not give freedom, simply putting any escape artist back into the tower.
The only escape from the realm is to accept the Tower's true meaning: great upheaval and disaster that brings about change. Denying its truth only delays the inevitable, and the Tower has a way of crumbling regardless.
The Star's Realm
The Star's realm, visited during Julian's route, is the beacon of light where the sea meets the sky. More precisely, it's a lighthouse, the beacon at its top made up of a thousand little stars that call travelers forward. Beneath the lighthouse lies a labyrinth with walls so tall they block out the sky. The walls of the labyrinth are made out of crumbling marble, and statues flank the great arched entrance. As the path goes further in, the geometry of the place becomes stranger and more unsettling, with stairs leading to nowhere and doorways bricked up or dropping off into a sudden abyss.
As the apprentice changes by completing the trials of the Star, the labyrinth transforms in response to those changes. If the apprentice passes the trials, the labyrinth becomes almost peaceful. If they do not, it resists the apprentice every step of the way.