The general idea is for a Naruto/Bleach type shonen setting.
The nations of Kasugai and Ichikawa have been in a cold war for centuries. Neither nation dares launch an all-out attack on the other, but fighters from both places have long battled each other wherever they met beyond the borders of either country. The two countries are separated by a great mountain range, each existing between the mountains and an ocean coast.
To ease tensions between nations, the leaders of the two countries have agreed on the suggestion of a neutral organization to hold a great mock war. Young warriors will battle each other in a great valley that lies nestled between the mountains. Both sides will seek to take as many prisoners as possible, until the other is forced to yield the valley. Killing has been forbidden, but those taken prisoner will be slaves to their captors for a period of one year until they are allowed to go home.
Unkown to either nation is that there lies another purpose to the war- A dark lord lies behind the organization that arranged the mock war, and intends to use the valley as a sacrificial ground to allow the spirit of a dark god, trapped for a thousand years in the underworld, to roam free again.
I'll have a list of general powers that every character can have. Each character can have a couple of special powers on top of that. this will be freeform, with a general power ranking given to each character as a guideline. The power ranking can change as the young warriors learn and train.
Warrior- A young warrior selected to take place in the mock war.
Warden- An older, more experienced warrior tasked with patrolling the mountains and keeping things in check.
Oni Guard- There will be a group of Oni Guard who will be, individually, the strongest characters in the RP at first.
This is an idea I'm throwing out there for now. If there's interest, I'll add more detail.