Mirror World

"A world of darkness, a world of eclipse, a world of demons, a world of...reflections. It is a literal definition of "what if" of our own world. An entire seperate universe...Dare you venture into the primordial mud?"

- Azazel gleefully describes the Mirror World Mirror World (鏡輿地, Kagami Yochi), also known as the "Silver" (銀, Gin), is a parallel universe/dimension that exists as a literal mirror of Earth Land, one enormous reflection of it, believed to have been "created" by the eponymous "Mother of Demons", Avora, as a safe haven for Demons. It is a complex and bizarre universe that embodies opposites of nearly every single aspect of Earth Land, from the dominant species, the names, and the states of day and night.

Description
The Mirror World is an almost perfect polar opposite of Earth Land, and although its true creation is a mystery, the most common legend involves it being a direct creation of the Mother of Demons, Avora, as a last resort for demons to escape to and be safe during primordial times. As its name implies, it is indeed a reflection of Earth Land, and much like how someone's reflection on a mirror is technically raising the left hand when the right hand is raised, the reflection of Earth Land displays things either wrong or simply opposite. The most prime opposite is the dominant species being demons, while the minority are humans. In addition, the day and night cycle is vastly different, as it is more often night, when it should be day, and becomes day when it is meant to be night, showing even the way the world and universe works is the opposite of Earth Land's, but is considered normal for the inhabitants of the Mirror World, to the point daytime is when everyone sleeps, and nighttime is where everyone is awake.

Interestingly, it does possess counterparts of Earth Land's residents, although the exact way they work is unclear, and their origin seems odd for a "created universe". The counterparts of the Mirror World are called "Mirrored" (ミラーリング, Mirāringu), and exist for every creature, being the opposite in every way, from their race, to their gender, and even their fate. For example, every living Mirrored who exists in the Mirror World still means their Earth Land counterpart is dead, and the same applies for an Earth Land inhabitant, although the exact point where their fates is decided is unclear.

Inhabitants of the Mirror World are aware of the existence of Earth Land, and in their world is known as the "Mud World" (泥輿地, Doroyochi), as some form of derogatory slur to it and its people, being viewed mostly in a negative light by the Mirrored.

Entrance
The entrance to the Mirror World is known as the "gap" (間, aida), an entirely black and white void of nothingness, existing as a form of seperate space that is considered the "mirror" that creates and connects the two reflections, the Mirror World and Earth Land. The gap can only be accessed via time and space-based magic, tearing a wormhole through the space-time continuum, although the chances of actually finding the gap is incredibly rare and nearly impossible. When entering the gap, a second wormhole must be created, which will actually lead to the Mirror World. However, an alternate, more successful method of entering the gap, and later the Mirror World, is via Mirror Magic, or any mirror-based ability, even a Curse, but requires the user to have incredible skill and mastery over Magic as a whole foremost. It uses a special spell that creates a mirror connecting between the current world and the gap, becoming a portal to it. The spell itself requires incredible amounts of power and concentration, but can be artificially created via machinery and magic items.

However, the gap is not unprotected. A powerful warrior, known simply as the Mirror Knight of Silver (鏡騎士の銀, Kagamikishi no Gin), who protects the path to the Mirror World, either forcing any unwelcomed guests back to their world, or killing them if they persist. Due to this presence, creating another passage to the Mirror World is sufficiently difficult, unless he is stopped, something that has supposedly never happened.

Terminologies
The Mirror World possesses terminologies and words that are counterpart to existing terminologies on Earth Land, the most common ones being:
 * Mao (真央, Mao) - essentially the Mirror World's equivlant of a Dragon, being almost identical physiologically speaking, even a similar hierarchy, being the most powerful species in the world. Their magic differs, however, as it revolves around manipulating the Mirror World itself as they see fit.

Trivia

 * The concept of the Mirror World is inspired by the common "parallel world" concept, such as Edolas itself, albeit more literal in terms of being a "reflection".