XSp.

Battle Royale, a popular manga in Brazil, has it’s origins on a novel that also has a movie adaptation:

Having watched the movie and read just a couple of volumes from the manga, I can tell that the movie cuts back on the sexual content, but still has lots of the gore.

For those who don’t know… the plot goes something like this:
Sometime in the future, Japan as a whole is collapsing with high unemployment rates and society crashing down.
Education went downhill with hundreds of thousands students boycotting schools and commiting crimes against teachers, having absolutely no respect for them.

With that scenario, the government promotes the Millennium Educational Reform Act, or BR (Battle Royale) act that states that every year a random school class in japan is selected, taken to an isolated area, and it’s students forced to play a “game” in which they have a limited time (3 days) to kill each other in a way only one student comes out alive.
If in three days there’s no “winner”, everyone gets killed.
Blood gushing moments, beheading, violent deaths and stuff like that are to be expected!