- You may be looking for the Vampire Wars.
The Second Time Front, (PROSE: The Brakespeare Voyage) remembered by some of its veterans as the eternal war, (COMIC: Doctor Who and the Iron Legion) was a conflict in the War in Heaven. It was bounded within the Second World War (PROSE: The Brakespeare Voyage) across many of the Known Worlds. (PROSE: Warlords of Utopia)
The Great Houses created the Second Time Front by modifying the timeline based on the many human "what-if" novels set during that time. (PROSE: The Brakespeare Voyage) This began during the House Military Wave of the same number, (PROSE: The Book of the War) before the horrors of the War had been fully realised. (PROSE: The Brakespeare Voyage)
House Mirraflex sent a Cwej called "Abschrift" to Germania I, one of a vast collection of parallel universes called the Known Worlds. He arranged an agreement with August Hitler in exchange for the technology needed to jump between Worlds, which would be used to organise the various German universes, called "Germanias", under one banner as the Greater German Reich. (PROSE: Warlords of Utopia) However, as Robert Scarratt later recalled, every change "made things worse", creating "time-fistulas, pseudo-cancerous Nazi spacetimes, spewing their hateful seed into the infinite." (PROSE: The Brakespeare Voyage)
Separately from the World War II universes, another cluster of the Known Worlds was composed of timelines where the Roman Empire never fell, called "Romas". After the accidental discovery of universe-jumping technology in Roma I, these Worlds banded together into the Empire of Empires and declared war against the Greater German Reich. Thanks to Marcus Americanius Scriptor's military strategies, Rome ultimately conquered the Germanias and stamped out Nazism. An agreement was reached with Abschrift's god that Scriptor would patrol the Germanic timelines in exchange for the continued safety and independence of the Roman Worlds. (PROSE: Warlords of Utopia)
House Lineacrux, an elderly member of which served as advisor-emeritus to the Front, would later take credit for the resolution of the conflict, with Plautus suggesting that his House had intentionally created the Roman universes as part of a "considerable metaphysical counterfource". (PROSE: The Brakespeare Voyage)