There is plenty that doesn't depict war at all and thus avoids glorifying it, but I'm unaware of anything fantasy that depicts war in a non-glorifying way.

This is a common problem of realist anti-war stories, too.

No matter what pacifist morals fiction seeks to expound, war is usually depicted as exciting, soldiers are beautifully tragic, etc. All of this is seductive and therefore not truly anti-war. The only genuine anti-war movie I've seen of is Come and See, which, uh...you should only watch if you're okay with being traumatized. It's free on Youtube these days though and is very good. Blood Meridian is a novel that manages to be similarly anti-war.

I disagree vehemently with those examples given here that I've read that actually portray war. For instance, The First Law and Malazan both definitely glorify war.

The Heroes is an action-flick anti-war movie in literary form--Abercrombie's war may be a messy and immoral business but it is beyond doubt excitable and seductive. That's what action flicks are for.

As for Erikson...come on. First of all he has all the faults of Abercrombie regarding the excitable aspects. He goes far beyond that, though--his soldiers are nothing if not glorified. They are heroes, men and women who sacrifice themselves in the name of compassion. If they pick up a few anti-social traits along the way, well that just makes their sacrifice greater. Witness the unwitnessed. You cannot read Deadhouse Gates and not wish you were there to help Coltaine and his 4th on their march across the desert, protecting the helpless (colonists) from genocide.

Of course, this is only a fault from an anti-war perspective. If we instead think that there is such a thing as a just war, or that war is not inherently evil, there is nothing wrong with Erikson's depiction. But it's not the slightest anti-war. It's basically the fantasy version of Saving Private Ryan: "Oh, it's such a shame the Nazis forced these American soldiers to be awesome and selfless heroes going through such difficult but cool and exciting trauma."

Red Rising? Come on, it's literally a (very good! I love it) power fantasy centered on just war. The Stormlight Archive? Uh...did we read the same book?

Been a while since I read The Black Company so I can't comment on that. Haven't read Pratchett yet.