Ganta's mother. She's shown to be a scientist working at the research facility that would become Deadman Wonderland 10 years later in the future. She's also the inventor of the Mother Goose system, which is used to restrain the Wretched Egg. Sorae and the DW's chief, Hagire Rinichirou, was the heads of the research on the Nameless Worms. Their brutal experiments on Shiro led to the creation of the Wretched Egg.
The main protagonist of the story. Ganta is a seemingly harmless, ordinary middle school boy who is framed for the slaughter of his entire middle school class, perpetrated by the mysterious Red Man. Sentenced to "death," he is sent to Deadman Wonderland, where he is initially confused and frightened by the brutality of the prison. Shortly after arriving, Ganta discovers he can manipulate his blood and, thus, is deemed a Deadman, a bearer of a Branch of Sin—a power that can turn blood into a lethal weapon. Ganta appears to have gained this power from a shard of crimson crystal the Red Man fired into his chest after the massacre at the school. As a Deadman, Ganta is forced to fight and survive in the Carnival Corpse under the moniker, Woodpecker, while trying to locate the Red Man, who apparently is held captive in Deadman Wonderland. Ganta's power, dubbed the Ganta Gun by Senji, allows Ganta to gather variable quantities of blood in the palm of his hand and then shoot them at high speed, as if they were bullets. While advantageous as a long-range attack, due to Ganta's small stature, this also puts him at risk of experiencing symptoms of excessive blood loss. Ganta participated in Scar Chain's attempt to escape from DW, and helped several members escape along with video and audio evidence of the atrocities being committed below the prison. Ganta, however, chose to remain behind to continue his search for the Red Man. Shortly after these events, Ganta's power began to change, evident by a strange tattoo-like mark radiating out from the crystal in his chest. His Ganta Gun now emits a much more powerful blast than before, though it is much less controllable and causes him physical pain. (Source: Wikipedia)
Senior leader of the prison's guard staff, Makina is a harsh and cold enforcer which does not hesitate in punishing, often brutally, the prison's population. Known for her demeanor and her large breasts (G cup), she is infamous for carrying a decorated sword with herself at all times, and also for using it to cut whoever breaks the prison's rules, acts that almost always result in bloodshed. Despite her brutality she is far less twisted than Tamaki, whom she is greatly suspicious of, especially after discovering that she knows and has authority over only a part of Deadman Wonderland. This fact, coupled with Tamaki's ever more sick machinations, led her to forfeit her position and hunt him down with the aid of some allies, among them the Deadmen themselves, Ganta in particular. After the death of Tamaki, she came in possession of the data regarding the Wretched Egg, the Deadmen and the Forgeries.
The Chief of Deadman Wonderland. He's the true primary antagonist of the series and he's also bedridden and locked inside his room, guarded by two albino twins. Due to his state inside an old man's body, the managing duties of DW prison are left to Tamaki. He's also a Deadman. He's killed by Shiro after challenging her Wretched Egg persona to a fight. It's later revealed that Hagire isn't actually dead, since he had transferred his memories to Sakigami Toto and is currently occupying Toto's body. In the past, Hagire who was in his orginal body and was the head of the research facility Ganta's mother, Igarashi Sorae worked in. They led the research on the Nameless Worms and experimented on a little Shiro; while Sorae was plagued by guilt due to the inhuman experiments, Hagire was shown uninterested in Shiro's well-beings and often sadistically pushed the experiments forward. In the end, the pains from many experiments forced Shiro to create the Wretched Egg persona (which she termed "Ace Man", a hero who saved the weak on a TV shows she and Ganta watched together), and developed the ability to control blood. Hagire's interests in Shiro skyrocketed after the Wretched Egg appeared, and he started to aspire to be like her. HIs branch of sin appears as tentacle-like whips, which he uses wildly and randomly, however, when he transfers to Toto's body, he gains Mockingbird's branch, Love Labyrinth
Chief of Intelligence for Scar Chain. His Branch of Sin takes the shape of a hexagonal shield with spikes on the side. He is the traitor that gives the Undertakers information about Scar Chain's breakout plan. (Source: Deadman Wonderland Wikia)
Kosugi is a Deadman and a former member of Scar Chain. He died during the Deadman mass prison break.
A squad leader of the Undertakers, Tamaki's special enforcement group which selects prisoners who could not be rehabilitated and survived a special 'correctional' program to be anti-Deadman soldiers, wielding weapons that allow them to nullify the Deadmen's Branches of Sin. He dresses like a monk (though he prefers to be called a "Hyper Monk") and wields a guitar that can split into two machine guns, fire shock waves, or just play music like a regular slide guitar. 2 years ago he killed Nagi's wife after she conspired with her husband to rig their fight, and has taken an interest in Nagi since then, claiming Nagi possesses the insanity befitting of an Undertaker. During the flashback in episode 12 Genkaku's past is revealed, describing the events that led up to his current insanity. As a young boy Genkaku was a monk at a monastery, where at first he was a quiet, gentle person. However after taking constant abuse at the hands of three other men present at the monastery (it can be assumed from the flashback that it was not only physical, but sexual abuse), coupled with the aftermath of the explosion in Tokyo, he snapped, killing all three of the men.