I have a very serious rec today for you all.
The story is
Hard Balance by
wingeddserpent aka
mako_lies Description: Getting to know someone is never an easy road, even when you're not trying to save the world. Spoilers for the whole game. Note: This work contains drug use.
This is, hands down, my favorite FFXIII story to date. The description is so simple for the masterpiece it describes. The first three chapters are a series of 'missing scenes' from FFXIII, all from Sazh's POV, focusing on Sazh and Lightning's developing friendship. After that, it's all Post Game conjecture of the best type, but I would not call it AU in any way. It ties in nicely with the upcoming sequel.
I'm not doing this much justice. Go and check it out, and be sure to tell the author how much you enjoyed her story! Maybe we'll earn some more Sazh/Lightning love from her if we're all very diligent.