What does Wally want to do exactly? Return to his own dimension at a point in time to stop the destruction?
If so what could be kewl to tie Wally to the universe he is in would be for him to work with the Quidnunc and realize that he cannot undo what has been done in the fashion he thinks. However, what if the Adversary was a being of such cosmic proportion that his existence transcends time and space boundaries and thereby, in a way beyond our comprehension, can, for lack of a better word, "exist" in multiple realities and times at once. Based on that theory, if the Adversary (whose Identity can be something completely different in our V & V universe..Wargod maybe
) was in fact, completely destroyed, it would undo his existence and wipe out his being and actions from all points in time. Thereby restoring Wally's universe.... theoretically.
Of course there is plenty of room for dramatic snafu's and continuing adventures to ensue from such a task.
What if removing the existence of such a being disrupts the balance of reality itself requiring great quests to undo the damage or perhaps permanent stewardship of the timeline to deal with devastating backlash anomalies?
What if other cosmic beings take offense to the disruption of the "natural" order?
What if in undoing the Adversary's actions realities are not neatly restored to how they were but are skewed into all sorts of horrible directions? The Dark Warrior becomes an intergalactic conqueror for instance..
What if something far worse comes to life to fill the void left by the Adversary's demise?
Oh its a cornucopia of adventure!!