Deadmen

Deadmen are people who are infected with the Nameless Worm which enables them to do extraordinary things with their blood. Most of them were infected during the Great Tokyo Earthquake.

During the Great Tokyo Earthquake, pieces of a certain Red Diamond were found. The Deadmen yet to come somehow inhaled or swallowed a piece of the Diamond. The Red Diamond is a capsule for the Nameless Worm and so the Nameless Worm settled in the bodies of the Deadmen and gave them the Branches of Sin.

The privately owned prison, Deadman Wonderland, is a facility where Deadmen are held (more specifically the G Ward). They are used to compete against each other in the Carnival Corpse. Tamaki did research on the Nameless Worm and was able to create artificial Deadman: the Forgeries.