Deadman Wonderland was canceled after straying from the manga. After being unjustly convicted of murdering his entire middle school class, Ganta Igarashi is sent to a privately operated prison where the prisoners are treated as grotesque tourist attractions.
The 12 episode anime is based off of the first 14 chapters of the anime. This would be everything from Ganta's friends being killed all the way to Nagi's death. But there are lots if things that should have happened in those 12 episodes that didn't happen.
Will There Be Season 2 Of 'Deadman Wonderland'? Unfortunately, there won't be any next season as Manglobe Inc. went bankrupt in 2015 because of a debt of about 350 million yen. This means that the show's creators, producers, and directors won't be able to make any other season as they must be unemployed.
Ganta is hereby sent to Deadman Wonderland. It was only later revealed that Tamaki was actually the Warden of Deadman Wonderland and that the Red Man deliberately framed Ganta for murder so that he could be taken to Deadman Wonderland.