Yamibo

Yamibo (闇某, Japanese for Dark One) is a being born from the collective evil and negative emotions of all forms of life in existence. His existence is recorded in several prophecies that date to before the foundation of the Gotei being refered to as "The Dark One" causing him to be viewed by most as a mythological figure with a similar role to Satan in Christianity. He is in fact a being of pure darkness who has been tasked with recreating the universe in a form that lacks any all all evil.

Appearance
Yamibo has no defined appearance while existing within reality, however in mythology he is always referred to as a "red eyed demon of the earth". Some variations of the myths also go on to describe him as deceiving man by assuming the form of a beautiful woman with dark skin and ebony hair. The truth is that Yamibo's appearance is determined by his host. While existing within a host Yamibo assumes their exact appearance as he exists as an extension of their soul. Whenever he asserts control or manifests his power though a host however their eyes turn blood red, a possible explanation of the "red eyed demon" description. It is also likely that one of his earlier hosts was a woman in possession of dark skin and hair, which explains his "trickster" appearance.

When in a plain of existence outside of reality Yamibo is shown to take a male humanoid form with gray skin and black hair and eyes garbed in a cloak of shadows. This form is shown to be near featureless beyond what was previously stated.

Personality
According to myth Yamibo is a vengeful being born of evil who wishes to destroy all that exists. In reality he is very apathetic, viewing emotion and other traits that make humanity what it is as, in his own words, "Useless" and considers them to be evil. As a result he has great contempt for humanity, the only thing close to emotion he ever displays. Despite this when he is shown in his true form he explains that he despises humanity, due to the fact that he was born from their evil and desire for a god. Upon his creation he took up the position of "God" and took it upon himself to rid reality of what he views as evil, which as stated is human emotion. To this end he began the cycle of destruction and recreation that consumed the Original Universe.

Powers and Abilities
Unknown Spiritual Energy: Being a Spiritual Being Yamibo has Reiryoku, however the exact amount is unknown. Based on the events attributed to him in mythology it can be assumed however that he is at least as powerful as the Spirit King and potentially even stronger, due to the fact the creation of the Universe itself is attributed to him in some versions of the myth. Due to always having to manifest through a vessel even when he appears before the Gotei it is impossible for them to determine his level of Reiryoku, due to there being a seamless blend between his and his hosts power.

Reality Manipulation
Yamibo's main power is the ability to alter reality itself. The degree of this manipulation varies. Early on in the series he could only affect small changes around his host, however as he grew in power he could cause greater and greater change in the world around him, such as allowing his host to defy the laws of Physics. Once he has reached a certain level of power he could even erase beings from existence entirely, causing history itself to rewrite itself.

Dead World: Yamibo's most devastating attack. Once at the peak of his power Yamibo is able to literally erase the Universe itself from existence, reducing reality to an empty black plane of non existence that he refers to as a "Dead world devoid of all Light". Once this Dead World is created Yamibo is able to gather the fragments of the previous reality and put them back together as he sees fit to recreate the universe.

Host's Abilities
Zanpakuto ???: Andrei's Zanpakuto.

Trivia

 * Yamibo's character theme is stated to be a remix of Dark Impetus and L'Impeto Oscuro