The main protagonist of the story, is a seemingly harmless, ordinary middle school boy who is framed for the slaughter of his entire class, perpetrated by the mysterious Red Man. Sentenced to 'death' after a phony trial, 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 allows the bearer to manipulate its blood, usually with lethal effect. 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.
Source from Wikipeida