Deadman Wonderland, Doubt Recommendations
Confinement, gore, and desperation encompass the psychological framework in these two series.
prisoners of a sick twisted game
forced to play the game of life and death friend becomes your enemy.
Another horror, and some similar characters. Deals a lot with friendship and trust in both.
Gore, a lot of blood and some of the best horror plots out there. That is what you will get when you start reading these manga. Both if them revolve around people who get caught up in a game where they have to fight in order to survive. If you like these kind of dark plots then these manga are perfect for you!