The Rider

Karlova and Margoth had been enemies for centuries--and now they were about to join in peaceful alliance through the marriage of Princess Mary and Prince Boris. But the Rider, the most successful highwayman ever to plague the two countries, secretly became part of the royal wedding plans. From the non, nothing went according to schedule.
Who was this mysterious brigand? What could he gain by sabotaging the two nations' only chance for peace?