Assassin. The Valiant Series, #4

Sold into slavery by his own parents at the age of seven, Aidan has spent his life enduring tortuous training in the arts of war. Now a man, he is an assassin in the service of his king. He kills whoever the king wants dead without question, regret, or concern for his own life. But when another assassin targets the king's daughter, Aidan's path to protect her will lead him down a dark road of corruption.
As he struggles with his duty and his conscience, Aidan finds himself falling in love with the person he is supposed to protect and falling away from his commitment to his king. As Aidan is consumed by the lies and darkness of his world, his past sins threaten to destroy everything he holds dear, including his love for the king's daughter. Can Aidan overcome the darkness, or will he succumb to it and lose everything?