Fallen Spartans Halo ( Book #2)

The book after Black Spartans.
Many years after the 'Cortana incident' The Black Legion are more of a nation then ever, they control more territory then the UNSC, and a mutual truce between the two keeps the peace. Mark Church, The leader of the Black Legion, is at the forefront of all technological advancements, his weapons ensure that the UNSC keeps its promise to the Legion, its ships allow for faster manufacturing. They have made new forms of power for fuel, traveled to distant galaxies, most that have never been seen before. But with new places, comes new dangers.

"Maybe we should have stopped after Reach."