Charles Widmore
In "The Variable", Daniel Faraday is shown to have suffered severe mental damage as a result of his experiments in temporal displacement, impairing his long-term memory. Charles Widmore promises Faraday that he will be healed if he goes on the freighter mission he was recruiting him for. Upon his arrival on the island, Daniel is cured of these problems, although he did suffer a temporary relapse after the death of Charlotte.