God

Your power, your life...I am taking them all.

An enigmatic entity referred to as God by Homeless Emperor.

Appearance
In its first appearance, it looked like a swirling gust of wind with flesh floating along with it. When it made its second appearance, it looked like a giant humanoid figure made entirely of flesh and bones with no face. It is unknown whether its physical form is the same, or they were just imaginary projections in Homeless Emperor's mind.

Personality
It appears to be extremely evil or devoid of emotion, wanting the eradication of all humanity, due to seeing them as "foolish", a sentiment that was shared by Homeless Emperor. It also seems to dislike failures, as it mercilessly takes away Homeless Emperor's powers and kills him after his defeat.

Monster Association Arc
After Homeless Emperor's defeat, the entity appears in his mind, only with its appearance being changed into a colossal giant of flesh and fractured bones. It then expresses its frustration at Homeless Emperor and takes away his power and his life.

Abilities & Powers
Not much is known about the full extent of its abilities, but it can be assumed that it is possibly one of the most powerful characters in the entire series, due to its ability to bestow power strong enough to make a regular man rise to a Dragon-level threat.

Supernatural Abilities
Power Bestowal: The enigmatic entity is capable of granting supernatural powers to individuals. It gave Homeless Emperor the incredible power of summoning energy spheres similar to little suns which explode on contact and create huge and flaming bursts. It is also capable of taking back the granted powers along with the lives of the wielders. It is unknown if there is a limit to how many people it can give powers to at once.

Mind Incursion: It was able to get inside Homeless Emperor's mind and communicate with him. It was also able to freely change the appearance of its projection in Homeless Emperor's mind.

Trivia

 * Murata stated that Homeless Emperor's energy-based powers are the same as Choze and Vaccine Man.
 * Like Homeless Emperor, Vaccine Man also claimed to be on a sacred mission to destroy humanity, but stated that it was "Mother Nature" he served rather than "God".