Changing a character's composition is harder than it would seem, well, in the context of my novel at least.  He goes from being a witness to committing the cold-blooded murder he originally saw.  He is no longer a witness.  He has gone from ghostly presence to something more concrete - or corporeal would be the better word; from complete victim to something still victimised but also more involved and eventually proactive as well as reactive.  He was never morally perfect, but now he descends into moral ambiguity.  Yet there is no way I dislike this character.  Perhaps because he dislikes himself.  I am not yet sure whether he is aware of how his choices long ago have placed him in this position, but, although we all have choices, some choices are simple in their starkness.  His choice was not so much to live but rather to have the chance of dying.  Faced with ultimate and never ending horror and pain (one conception of hell, surely), he chooses life even with the almost intolerable burden of what he must do to retain it.  Powerlessness personified.  Perhaps that's what I'm about - exploring powerlessness, though I don't want to know what is behind all this, and I think it's more about choice and how the choices we make change the world, but I still don't want to know.  That's for others to decide.  But choices have ramifications that extend way, way beyond the personal sphere and this poor character's choices have left him in a place where his choices have lost all pretension to black and white - they all all grey, no matter which way he looks.  As grey as his previous life, as grey as the life that stretches ahead of him and I don't know, for the moment, whether that life will be pleasant or terrible in its solitariness.  I really feel for this character.  He never had power in either a personal or a social sense, and yet, I also know he will make good use of a power lent to him for a specific purpose.  He will 'abuse' it in that he will attempt to atone.  Not sure whether he will manage it or not yet.
The only thing certain is that he is no longer a ghost and will commit cold-blooded murder.  It's the latter that's going to be hard.