The Heroes by Joe Abercrombie might be good too. Here's the author's description:
Three men. One battle. No Heroes.
It is stand-alone although there are some cross-over characters with the First Law trilogy. I haven't read the First Law books yet, so I don't know if there are spoilers in The Heroes for those books, but the reviews I scanned don't indicate that there are.
One of the comments there also mentioned Glen Cook's "Black Company" books which look like they meet your criteria too. Again, I haven't read them, but have heard good things about them.