Mech 1: The Parent (Imperium series)

Bio-tech aliens battle Mechs built by humans!

After centuries in stasis, a lost task force returns home. Arriving from the infinite void the surviving ships discover that the Imperium lies in ruin. The Homeworld itself is destroyed, and nothing lives in the Ancestral System except an infestation of unknown bipedal beings--creatures soft, red of blood and warm of flesh...

When you colonize a planet, make sure the owners aren't coming back...

MECH is the story of a new Earth colony built upon the ancient Homeworld of a civilization presumed (incorrectly) to be long dead. MECH is a full novel, 90,000 words in length, by bestselling author B. V. Larson.