Fallen Blade, book 4: Blade Reforged
Kelly McCullough2013

After the fall of the goddess of justice, temple assassin Aral Kingslayer lost his purpose in life and turned to the bottle. That might have been the end of him if luck hadn't given him a few people to help him get back on his feetnotably the irresistible Baroness Maylien Dan Marchon, who once sought his aid in claiming the throne that's rightfully hers. Reluctant to resume the role of an assassin, he turned her down.

But now Aral has learned that one of the few people willing to help him in his darkest days has been imprisoned by Maylien's uncle, King Thauvik. Aral knows he can't let an old friend die, but the alternative is to return to the life he left years ago. It was the death of Thauvik's half brother that earned Aral the name Kingslayer, and now he is thrust into a war that will see no end until he lives up to his name