Nick Valentine is synthetic humanoid A.I., or synth, created by the mysterious organization of scientists called The Institute. He lives in Diamond City, working as a private detective for hire. Even though synths are generally regarded by people as a threat, the citizens of Diamond City eventually warmed up to him.
Valentine does not know precisely when he was created by The Institute, but he believes that he is a prototype between the first and newest generation of synths. His personality and memories are those of a pre-war police detective, who volunteered to donate his memories to The Institute (then known as Commonwealth Institute of Technology).