Shunned from the colony

I only remember pieces of this dream, but I start off as this young boy living in this colony. I was friends with this girl (had a really strong love for her), and we both had older brothers. Our brothers were some of the protectors of the colony. I think we lived in a world where strange monsters attacked humans. One day in school, a strange boy showed up. At first everyone could see him, then he starts messing with me and threatening me. He kills my brother and I was there to see the death, when I go to our leaders to say what happened, they have no idea what guy I’m talking about. Some how the whole town thinks I’m crazy and I killed my brother. I go to my friend and she is the only one to remember. I get kicked out of the colony and somehow obtain these weird demon powers. I go back to try and find that strange kid and I’m shunned by everyone. My friend’s brother ends up helping me realizing that I wasn’t lying, so the two of us and his sister (the person I love) try to clean my name and avenge my brother.