Comics have been written about war for almost as long as they've existed. Why? War creates heroes and legends. The inexplicable happens, and the expected doesn't. War comics also have a high percentage of true stories, or based on true stories. Keep in mind this list is far from exhaustive, merely a selection of works I've read.
Fax from Sarajevo: Joe Kubert's account of faxes he received from a friend during the siege of Bosnia and Herzegovina. A combination of portraying his own life, and the faxes from his friend telling of their struggles.
Last Day in Vietnam: A collection of Will Eisner short stories from US soldiers in Vietnam. At times touching and hilarious, sometimes at once.
DMZ: Brian Wood and Eduardo Burchielli explore life following a journalist during the Second American Civil War, in the DMZ of Manhattan. The changes and dangers he faces are followed, to his rise as an influential political figure.
Crecy: A Warren Ellis telling of the battle of Crecy. The story follows a narrating soldier following the King in his campaign against the French.
Peter Panzerfaust: Part Peter Pan, Part WWII resistance fighter. The story of a young man leading a resistance group against the Nazis.
Enemy Ace- Another Joe Kubert creation, about an honorable pilot on the other side in WWI. A good man facing his darkness, and the darkness of his people.Later applied in some stories to WWII by Garth Ennis.
Unknown Soldier- The nature of the story depends on which era you're reading from, but he handles some nasty things during war. The Garth Ennis version has him trying to recruit his replacement.
Dreaming Eagles- Garth Ennis tells of black fighter pilots during WWII, the discrimination they faced, and the progress they made.
War/fix- The story of a journalist that gets hooked on the thrill of the dangers of war. He realizes he doesn't know how to function as a normal journalist, and seeks more dangerous embeddings.
Other characters to look for:
Sgt. Rock- DC's WWII army grunt. Nick Fury and the Howling Commandos-Marvel's equivalent property
Johnny Red- A WWII British pilot stranded in Russia, who takes command of a fighter wing.
Part One: Crime and Part Two: Spy
When you play Social Justice, the world loses.