Denizen

A Crimson Denizen ( 紅世の徒 ) or simply called Denizen ( 徒 ), is an inhabitant of the Crimson Realm. They have to consume power of existence in order to maifest themselves. Each denizen appears with their own distinct flame color. Some are known to have a human form.

History
In the very distant past, Crimson Denizens, residing in "an adjacent world  which cannot be reached, began to sense and resonate emotions given out by humans. Their desire to explore their curiosities as well as escape from the harsh environs of their world led to a Denizen to create a technique which allows them to cross the "Abyss between the Worlds and arrive into our world. And by absorning Power of Existence from humans, they would manifest in various forms and begin to roam our world in order to fulfill their various desires.

Prior to the "Spiral Organ" Leanan-sidhe's invention and popularization of Fuzetsu, most Denizens blended and mingled with human societies. In ancient times, they would openly appear to humans as various mythological gods, demon, faries and even wizards. Though by the latter half of the 19th century, due to advances in human society as well as the increased Fuzetsu, they began to hide their true form and assumed human form.

Characteristics
Crimson Lords and Denizen have existed for millenia, and though they do distinguish between young and elderly Denizen, there is no mention of whether Denizen "die naturally" or even how old they are. Upon being "born" in the Crimsin Realm, they immedaintely possess consciousness and knowledge of their powers and begin their struggle for survival right away.

They possess emotions which are basically similar to that of humans, in which they are able to get drunk, enjoy food, feel angry at comrades getting annihilated, fall in love with each other or even humans. As with humans, Denizens too have gender differences (though slightly different from humans in a stricter sense), and are fundamentally able to replicate their existenses in a way which is similar to how living beings in this world reproduce.

Crimson Denizens which come to human world usually possess two distinct names: the True Name and Alias. True names are given to them since their birth in the Crimson Realm and refer to their traits and powers they possessed. After coming to this world, Crimson Denizens usually nammed with the alias that mostly comes from; In human world, true name becomes like a surname,while alias functiones as a first name.
 * Humans that fear and rever them
 * The utilization of the other Denizen's alias
 * Mythical or folkloric names from human history
 * Oneself's fondness

Crimson Denizens, both allies and enemies, mostly call each other with their true names. In organizations, some high ranking Denizens have their subordinates calling them only by their true names. On the other hand, aliases, functioned like human' first name, are used with someone they are more intimate with. However, when Crimson Denizens meet each other or enemies, they usually, as an etiquette, introduce themselves with both true names and aliases. As same as japanese naming order, the introduce the true name (surname) first and then followed by the alias (first name).

Powerful Denizen are called Crimson Lords, though the difference between a Crimson Lord and a Crimson Denizen is only in their strength. For both Crimson Lords and Crimson Denizens, some would choose to maifest in human form, while others would opt to maifest in forms which closely match their "essence" fromt the Crimson Realm. thus appearing as "gods" and other mythilogical beings.

While a Denizen's growth and survival depends on his/her innate talens, their ability to learn and adapt also allow them to evolve into a Crimson Lord.

Similar to Torches, when they are annihalated, all human memories of them and objects they leave behind would disappear. However, some are able to make a record of their existence via encrypted texts and glyphs. And if a human were to make such encrypted recordings, their existence would be remembered as legends and myths. Flame Hazes are able to remember a Denizen who has died, even though they are humans.

Abilities
They are able to freely maipulate Power of Existence, as well as the ability to empathize with strong emotions and intentions from far away. There are many ways in which Power of Existence collected can be used, from manipulation spells to the creation of Rinnes to the creation of Treasure Tools.

The reason Denizen could absorb Power of Existence from humans is due to the similar spiritual and emotional foundations between the two species. While Denizen are also able to absorb the existence of non-humans, including dead objects, the Power of Existence provided would insignificant for their needs, hence they mainly feed on humans. Though the forbidden technique, City Devourer, allows a Denizen to devour a huge amount of existences of both humans and non-humans by refining them into a highly concentrated existences.

Denizen are able to utilize the Power of Existence which they absorbed for various things, though the ability to control these varies between each Denizen. Crimson Lords are called such due to their ability to manipulate large amounts of exisrences. Though for both Denizens and Lords, if the amount of existences used exceeded the amount of existence stored, then they would end up getting themselves destroyed.