Mercedes Lackey 
Redoubt [EPUB ebook] 

Mags, a Herald trainee in Haven, the capital city of Valdemar, has talents not commonly found in Collegium students. Recognising this, Nikolas, the King’s Own Herald, enlisted him as his undercover partner. Although his unknown heritage initially marked him as outsider, life at the Collegium has definitely improved for Mags. He’s even become something of a hero after risking his life to rescue Amily-daughter of Nikolas-from kidnappers hired by Karse, Valdemar’s long-standing enemy. But Mags knows the mysterious Karsite assassins are still out there, hunting him. Why is an even deeper mystery. The answers can only be found in the most unexpected corners of Mags’ past… if he can live long enough to find them.