Maybe you could read some stories that others have posted and see what kind of things you enjoy in them? I don't really know much about fiction writing so hard to say what to improve... all that comes to my mind is changing the plot to something more simplier and to more resemble something that could happen in the game (universe). For example in DOA4 story (don't remember whether it's Leifang's or Bass') Bass comes angry out of threater throwing people to walls and stuff, and Leifang tries to stop him/teach that bully a lesson. I think you could get some ryona story out of that for example.
After 5:00