Bearing an Hourglass by Piers Anthony, Del Rey 1984
Bearing an Hourglass by Piers Anthony is the second book in the Incarnations of Immortality.
Like it's predecessor, On a Pale Horse, Hourglass is a self-contained story with the same overall plot and characters.
That plot is Satan's hostile bid to wrest control of Earth in his ongoing battle with God. Those two are Incarnations, just like Chronos, the main character of Hourglass.
Like, Pale Horse, Hourglass follows a regular human, Norton, who stumbles into his new found office as Chronos, Incarnation of Time.
Immediately after assuming office, Chronos finds himself ensnared in Satan's plot to change an event in the past so he can gain political power on Earth.
The book is extremely entertaining, but the time travel aspect of it makes the story difficult to follow. Throw in the fact that Chronos lives backward so the people he interacts with talk backward and that he Satan traps him in illusions, and there is a lot of re-reading going on.
Not as good as On a Pale Horse, Bearing an Hourglass doesn't disappoint, and makes me eager to read the next book in the series.