Can all of reality be saved? Should it be?

Will Baker. Boy from the backwoods. Messenger to other realities. Spy for the secret rulers of his own…
The war to destroy everything continues and only one man has a chance to repair the damage before it’s too late. To stop the enemy that seeks to remove him and everyone he’s ever known from ever having been at all.
It isn’t lost yet, which can be told by the fact that he still survives.
Can he continue to do so?
More, in the end, is that the right thing to do?