I’m not sure how old the book is since it was from my middle school reading teachers personal connection. I don’t remember much details but it was a long series focused on a couple of different characters. The most memorable were an ex soldier(? Or just a warrior?) who used the sword but gave it up to become a monk. Eventually some stuff happens and he becomes some hardcore warrior/killer again. The second memorable character I can think of is a big, muscular guy that wields a giant double sided axe. The only thing I remember about him was that in combat his comrades couldn’t get near him for fear of also getting diced in half (he seemed like a berserk type). There were some books in the series focused on the individuals story but one or two books I read included both characters.
Lost Classics of Teen Lit: Name That Book! 