DO NOT, and I repeat, DO NOT try an ODST FF unless you can follow them canon-like.
An idea for you? Try smaller stories before a full-out FF.
But if a FF is your main desire, try something like a Marine's Diary found after a huge fight and hold-out in something and ..... you get the idea.
In my times, the darkened days,
Evil invaded the world.
We farmers,
We workers of the Red Union,
We united and slaughtered them all.
The brave soul,
Above the evil,
Planted our inspiration atop their burning cities.
- Ruski