Warhammer: Above and Beyond by Denny Flowers (Author)

An Imperial propagandist meets the flying ace legend he created, to prepare her for the most difficult battle of her storied career.
Flight Commander Lucille von Shard: Hero of Bacchus, fighter ace, and a living legend heralded for her valour and piety. Propagandist Kile Simlex, responsible for her fame, shares none of this renown. Condemned to the ignominy of a scribe's cubicle cell, his chance at liberation comes as a cryptic vid message claiming to be from Shard herself, requesting his aid.
Under the von Shard family's patronage, Simlex journeys to Deighton, a world in open rebellion from the Imperium, where he finds the commander a shadow of her former self. Near broken by eternal war, her confidence and reputation crumbling, Shard must somehow steel herself for her deadliest battle yet, against a xenos mercenary of unparalleled skill. Can Simlex help her overcome this near-invincible enemy, or merely watch as she is finally defeated?