Halo by Eric S. Nylund

The Fall of Reach

A sweeping military science-fiction origin story that follows the childhood abduction and brutal augmentation of a group of child soldiers, their years of ruthless training and bonding as Spartan super-soldiers, and the moral conflicts of the program's creators as a galaxy-spanning alien theocracy invades human worlds; at its center is a lone, nearly mythic warrior who must lead desperate defenses against overwhelming odds, protect a vital artificial intelligence, and survive the catastrophic fall of a fortress world that sets the stage for humanity's fight for survival.

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