Warhammer 40k Greater Good

"When the world of Quadravidia comes under attack by the insidious Tau, only one man can defeat the aliens and save the planet in the Emperor's name: the legendary Hero of the Imperium, Commissar Ciaphas Cain. When the aliens call for a ceasefire, Cain expects the worst, and his fears are answered in the form of a dread menace - the Tyranids! As a hive fleet approaches Quadravidia, Cain must try to forge an alliance between the Imperium and the Tau, but can he truly trust the inscrutable Xenos?"