I.A.N., or Intelligent Artificial Neuronet, is a top-secret creation from the combined efforts of Wayne Enterprises, Stark Enterprises, the Joe tech team, and other as-of-yet unidentified parties.
While Stalker has convinced the team that I.A.N. is a man in a mask, the truth is that he is a fully functional, fully self-aware, fully-artificial being. Programmed with all available knowledge concerning combat, the undead, and other topics, I.A.N.. All of which makes I.A.N. capable of acting independently indefinitely.