Asteropê I have not read this yet (but I have read the prequel), but I'm assuming you're referring to the main character? He's not a psychopath. He is/was a government sanctioned assassin, murder merely is part of his job description. Totally different motivations and reasoning between that and a psychopath or serial killer! Most people would not consider the Navy SEAL Chris Kyle, who in his career killed 160 (confirmed by the Pentagon, no doubt the real number is higher) as a psychopath. He's NOT! But killing was part of his job description and he did it on behalf of the US government. The character in this book had a "career of state-sanctioned murder" - meaning the government sent him and told him who to kill. He's more like Jason Bourne than Hannibal Lecter. So no, it's not implausible for him to get a conscience. And the fact that he has PTSD induced by his career, that the past haunts him, also leans to him not being a psychopath.