I don't know the fandom that surrounds this, but the writing is very good! You have good description, but within the action so it doesn't drag on. Your fight scenes are perfect. Not a blur, but not dragged out too far so that it feels like nothing's actually happening. Your plot hooked me in immediately. I didn't know what was going on, but I loved it. If the rest of the story is like this, you're gonna go far.