Leviathan

How does a peaceful distinguished officer of the Braymos homeworld become the most terrifying threat to an entire galaxy?
Leviathan, the last of his kind, seeks a way to reverse the annihilation of his people. With a menacing source of power behind the warship Areoso, Leviathan receives a transmission from a sentient world long since forgotten. Recalling their superior intellect and the power of the sacred crystals they would protect at all costs, he seeks to wield them for his sinister plan.
Back on Earth, Alexandra Greenwood and her half-brother James are thrust into a race against time to secure the eight sacred shards of Oubla before Leviathan's arrival. Reeling from the inexplicable threat by the last surviving Arinian and encountering dangers along the way, they discover an ancient secret from the past that may decide humanity's future.