Gareth

When second son Alexander Valentine loses his brother to an assassin's arrow, he discovers that his family protects an ancient secret and reluctantly finds himself at the center of the final battle of a war that was supposed to have ended 2,000 years ago.

The White Tree (book one): In Mallon the dark magic of the nether has been banned for centuries. Its users have been driven out or killed. Its secrets lost. But the holy book of the nethermancers has just been found by a boy named Dante. As he works to unlock the book's power, he's attacked in the street. The nethermancers aren't gone—and they want their book back. Caught between death cultists and the law, Dante fights for his life, aided by his growing skills and a brash bodyguard named Blays.