Columbus Day by Craig Alanson

Earth is caught in the crossfire of warring alien empires, and humanity is pressed into service as expendable allies. A wisecracking soldier shipped off-world begins to suspect their protectors are just as dangerous as their enemies, and everything changes when he awakens a snarky, ancient artificial intelligence with astonishing abilities. Together they hijack a starship and navigate treacherous alien politics, using wit and audacity to keep their people alive in a fast-paced blend of military action, humor, and high-stakes intrigue.

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