James Blish's Black Easter ends when World War III and Armageddon occur off-stage. We are told that the demons have won the latter. Near the end of Poul Anderson's Operation Luna, gods and demons fight onstage. The gods win.
The Day After Judgment, the sequel to Black Easter, ends when Satan declares that mankind must begin a long evolution towards Godhood and undoes the effects of World War III. Operation Luna ends when an archangel undoes the effects of the battle between gods and demons.
Parallels between these works by Blish and Poul and Karen Anderson's The King OfYs are discussed here.
Operation Luna is the sequel to Operation Chaos. A parallel between that work and The Day AfterJudgment is noted here.