[Matrixbeast]

Here's an idea: The story is about anonymous online users setting up their own personal fights, basically selecting a power (The Rider). The person who wields the power is seen as disposable, and they're basically sent in and forced to fight monsters (And other riders, should they rise up) for the spectacle of the online users.

Main story begins when our innocuous anon who just enjoys seeing action and violence is soon abducted and forced to become a Rider (I'm thinking the Riders are cyborg augmentations). Our anon, knowing full well what's going on because he was a former viewer of the action, has to endure through the leagues of monsters and soon, other Riders as he tries to end all this misery as well as help others.

Add in some introspection of who he is, some drama over other Riders having lost their humanity because they've been participating in the sick game for so long, and some glimpses of hope as a few others still have some morality, and boom.

Think online gladiators, but instead of a pit, it's a live stream, and instead of appeasing one man, it's the thousands of people watching online, some who think it's fake, others who know full well it's real, and some who just want to see some good ol' fashioned violence.