Chaos. Nomad Series, #4

Twenty-five years ago, two futures were changed. Before becoming a Nomad and a Hunter, brothers Daegan and Brayden Sawyer were like everybody else on Foundation Earth. Then Daegan leaves for a school trip, a decision that would lead them to travel very different paths. With his older sibling declared dead, Brayden's grief causes him to spiral out of control. After being banished by his family, he becomes even more self-destructive.
When he's arrested and given a death sentence on the infamous Tyrat Prison, he realizes how far he's fallen. However, Daegan is alive, though he may wish otherwise after discovering he's the latest recruit for the cyborg project. Years later, he finds salvation on the battleship, Ares. With their help, he becomes Gryffin and carves a formidable reputation for himself. Chaos follows them as they fight their own demons and strive to find who they were always meant to be.