Great setup!  (Did anyone else wonder if Belldandy ever needs venting out her
frustrations in a similar violent manner?)

I think you missed the point.

It's NOT a set up. It's a basically complete fic in itself. Belldandy 
was just an aspect of the Kindly Ones. They punished Keiichi, he's 
dead, gone. Can't be continued.

The fic by Nikholas F. Toledo Zu was basically a "What If the Oh 
My Goddess Fates were really the Sandman Furies"?