The Apprentice

You are the apprentice of an assassin who took you in for his own gain. He's handsome, highly intelligent, petty, stubborn sort of like Chrollo from Hunter x Hunter. He teaches you basic schooling, how to fight, shoot, deceive people, cover your tracks, and makes poison. He creates his own lethal poisons and he injects himself to build resistance against them, since he doesn’t make antidotes. Injecting you with his homemade concoctions you somehow gain the ability to read minds, sense one's emotions, intense strength and agility, as well as intelligence, and get partial glimpses of the future. He's tough on you at first, but over time he learns to let his guard down and like you.