John Cadaver

John Cadaver is the leader of the organization and (later explained in Chapter 39) the people, Black Dust.

Personality
John is a mysterious man, only showing himself twice for the moment, once in front of Gabriel X, another time in front of Angel IV. He is extremely ruthless, as seen in Chapter 39, where he says that he'll "do anything to protect his people, no matter the cost".

Relationships
He has only talked to both Gabriel X and Angel IV, so there isn't much to talk about in terms of relationships.

All we know is that he loves his people very much, but it could also be his downfall in the next chapters. Although, he did show respect to Gabriel X, and said that Angel IV was "a crazy man". Gustav also joined his organization, finally freeing himself from the dark clutches of Angel IV

Plot
John threatens the Union once it is formed, and is a sub-villain in Vol. 3. The Union and Black Dust become balanced by the end of Chapter 32, because of Angel's truce with them.

In Vol. 4 he was seen making a truce with Gabriel X to help with the Rebellion, after Angel IV decided to start a war against them. There, he shows his true colors as a person who did care about lives, but he cared more about the lives of his people.

Powers and abilities
Reset: In Chapter 41, he resets entirely Gustav, making him lose his memory in the process. This did remove the fact that Gustav was a horcruxe in the process.

Dark technology: In Chapter 32, he created an airship, with the same weaponry than the Black Beacon.

Trivia

 * The dude never appeared in Vol. 3, despite being the villain
 * In the beginning of his character, he was supposed to be an extremely evil emotionless psychopath. Now he's just a sociopath.