The Crown Tower (Riyria Chronicles‪)‬

Two men who hate each other. One impossible mission. A legend in the making.

Hadrian Blackwater, a warrior with nothing to fight for, is paired with Royce Melborn, a thieving assassin with nothing to lose. Hired by an old wizard, they must steal a treasure that no one can reach. The Crown Tower is the impregnable remains of the grandest fortress ever built and home to the realm’s most prized possessions. But it isn’t gold or jewels that the wizard is after, and if he can just keep them from killing each other, they just might succeed.