Faboamanto and Joanna I was thinking about this who he really is. And answer isn't easy.
He was born as John Bateman. He meet Maya as John. He loved her as John. He meet Vaughn as John.
Lucas North was other person, he was John's "let's call him" friend. Lucas had his own life, priorities etc.
John made his own choices: he worked with Vaughn, he made terrible mistake, he killed Lucas.
We don't know how much this situation changed him inside. Maybe to be Lucas and to make things like Lucas should was some kind of redemption. At the end he had terribly damaged soul.