Have You Heard This Before?

I am doing a manga comic (I'm no pro, I'm just gonna put it up on youtube) and I don't wanna copy anyone, so I just wanna know, have any of you heard this story idea before. In a medieval setting, two great nations are at war in secret to the public. And when the public learns of this war, all the peasants, and commoners from both sides come together, and start a rebellion, because the reason that they so poor, was because most of the natural resources and supplies that would have gotten to them were instead sent to the war effort. Although, this rebellion quickly becomes much more sinister then what was originally intended, so someone steps up to lead the rebellion back to its original plans (he is the main protagonist, but I haven't thought of a name) This story shows allot more war style/large combat fighting, but when they do fight one on one, most of them use talismans to help them fight (some talismans are more powerful and unique than others, and those ones get names to them and become known far and wide, where as others tend to have many of the same talisman and are weaker, and the final type of talisman are talismans that help other talismans be more powerful) The main character gets a powerful talisman (among other weak ones) called polygon (I'm still toying with the name of the actual manga, but I'm thinking of calling it polygon) and this talisman gives him the ability to teleport (to an extent) And other than that I don't have much more to the story to tell you. So, again, please tell me if you herd any of that before (and I know I shouldn't care since I don't know if I'm copying anyone but I just want it to be original) Also, tell me how I could change it to make it better, or if you have a name for the main character or a title for the manga, or something like a new character, that would all be good too. Thx for answering, and sorry for it being so long.