Dave, who only seems to show up at the most awkward times, chooses this moment to pull out a magical pair of dice to explain to Will the history of conflict between good and evil.
Well, "evil" might be pushing it. They call the time of conflict "the Great Unpleasantness" (37.37), like having really dry skin during the winter.
We'll keep this short. The good guys banished the bad guys to the Never-Was. Now they're back.
The Black Caps are the bad guys' human minions working to bring them back.
Will is an "Initiate. A member of the Hierarchy" (37.52).
Whatever that is, Dave doesn't specify.
Then the lights go out. Again. The Center needs to invest in a generator.