Warlords of Utopia is an original novel by Lance Parkin set in the Faction Paradox universe.
The glorious Roman Empire has ruled for nearly 27 centuries when Marcus Americanius Scriptor acquires a strange bracelet from a mysterious stranger.
With the bracelet, he finds that he is able to travel to alternate Romes in worlds where the course of history has diverged from the one with which he is familiar.
Worlds he finds later have no Roman Empire at all, and a cruel new regime in Germania on a path of conquest.
That leads to a conflict between all the parallel universes in which Rome never fell and all those in which the Nazis won World War II.