The Corrupteds' War may refer to two things, either the title of the third book in the chronology of the Parallel Planes series or to the war between the Corrupted and Thodore and his companions.

The novel depicts the events of the war. Almost exactly one thousand years before the beginning of Sword and Sin, a true Half-Dragon named Thodore managed to end a terrible war where a group of people known as the Corrupted Summoned something from the other plane and destroyed nearly all civilization.