Third, when you then factor in that the book puts the spotlight on women soldiers - in a comics marketplace where titles starring female superheroes are dropping like flies - it's almost a miracle that the project was given a green light.
It likely would not have been if not for Ennis, but it is clear his heart is in the project.
The man perhaps best known for over-the-top scenes of violence masterfully depicts the chaos of war with brutal, detailed panels worthy of "Saving Private Ryan."
While portraying German troops in World War II as sympathetic has caused controversy for publishers in the past (see below), Ennis gets away with it by simply showing them as soldiers who experience the universal glories and horrors of war.
Ennis differentiates this work by putting the spotlight on women at war and has based his tale on a true story (though the characters and locations are fictional).
This is where Ennis's research pays off, since it is true that the Soviets used women in a number of WWII combat - snipers, medics, tank drivers, machine gunners and pilots.
Ennis masterfully breathes life into his female fighters, who in the summer of 1942 arrived on the Stalingrad front to fly night interdiction missions in obsolete PO-2 biplanes.
Their nocturnal tactics led to the Germans nicknaming them the "Nacht Hexen" - or Night Witches.
Of course, it's not all sunshine and rainbows for the Soviet female pilots.
They are verbally abused by their major, but this comes across as the dehumanization all soldiers endure to prepare them for battle, rather than sexism.
Of course, degrading insults are the least of their worries, especially being female pilots.
This is brought into horrifying focus when a German squad leader - enraged by the number of soldiers killed by the Night Witches, decides to take out his frustration by having his squad gang rape a Russian teeanage girl. It is the most chilling such scene I can remember since the film "Caualties of War."
It is the Night Witches' resolve in the face of such potential danger and chaos that helps make them strong characters, as does Ennis' dialogue and ability to flesh them out. This is a great and powerful piece of work that can't help but affect those who read it.
With "Night Witches," Ennis touches on what has been one of comics' (and entertainment's) third rails: Portraying German soldiers during World War II as regular Joes rather than as Nazi stereotypes.
Former "Captain America" writer Mark Waid once famously had an origin story he had written for the Red Skull rewritten without his knowledge because Marvel felt the story put the Nazi in too much of a sympathetic light and might offend people in general and Jews in particular. It didn't matter that Waid is Jewish.
"It's important to remember that the characters in the Night Witches are soldiers, not Nazis - they're regular German Wehrmacht as opposed to Waffen SS," Ennis said.
"Some of them, most notably the sergeant, do make reference to Nazi ideology, but their driving motivations are a desire to survive and the anger they feel at their tormentors, the Night Witches.
"There's no doubt that brutality, rape, looting, torture and massacre played a part in the experience of almost every German military unit that saw service on the eastern front - a product of the intensely vicious nature of that campaign - but it was mostly only the SS that acted out of any sense of ideology."
"Finally," Ennis added, "remember that soldiers are soldiers, not caricatures. They'll talk about whatever's important to them at any given time, they won't just sit around spouting slogans." *