Dawn Wars

Dawn Wars are a series of conflicts that are spoken of in some of the oldest and most cryptic of texts. They are considered by most of the initiated as mere myths. Those that do decide to investigate the credibility of those myths, however, either vanish mysteriously or obtain unmatched powers while gaining access to weapons and knowledge that by all intents and purposes shouldn't exist.
According to those myths, during the Dawn Wars Mankind rose against the Powers... and not only survived, by either fought them to the stalemate or even triumphed against them. The sceptics point out that if so, then the current status of humanity as the tail-end of the supernatural ecosystem would make no sense. The realists respond by saying that it makes perfect sense - if Mankind was even worse off beforehand.
Some of the texts claim that the exact number of the Dawn Wars was thirteen. Some of the most abstract and confusing of those indicate that at least one of them hasn't happened yet and that the struggles of the modern Initiates against the horrors out there is a part of this still ongoing conflict.

The Conflict

Battlefield

The conflict was mostly limited to Earth, but there are signs of battles fought within the Elsewheres, suggesting that at least at some point the fighting spread there. However, considering the non-linear timeline of the Dawn Wars, its eventual retcon from history and the interruption of causality links between various Elsewheres, finding conclusive evidence about details is next to impossible.
Despite the Dawn Wars never happening, some of the battlefields (or the sites of major events) of it can be visited if one is determined enough. Returning from them, however, is something else entirely.

Historical Significance

The Dawn Wars are a great mystery mostly because they have never happened. Someone (or something) have manipulated the timeline itself multiple times. At the end of each one of the Dawn Wars - when either Mankind was driven into effective extinction or insanity, or Earth was no longer habitable - someone or something has pushed a reset button. Making the war never occur, yet altering the resulting timeline with at least some of its results.
This mechanism included only the Material Reality, for the results of the resets didn't spread to the Elsewheres. As a result, exterminated aberrants (or, if some myths are to be believed, dead Powers) remained dead. Why exactly the Dawn Wars ended with the current state of the world is a question that many scholars ask themselves.
The theories range from Powers winning the war, Mankind deciding that continuing the war was pointless or carried too much risk, Mankind and Powers reaching something resembling a truce, or the current situation is enough of an improvement from what was before that Mankind settled on it as a victory. More esoteric theories suggest that the Thaumaturgic Wars are still ongoing.
Whatever the truth was, the entire human history was shaped by the Dawn Wars. With what we consider to be past events truly occurring, yet their flow is clearly influenced by what happened during the concurrent Dawn War.

Start Date

???

Ending Date

???

Conflict Result

Unknown [Presumed Human Victory]

Belligerents

Mankind

Powers

Strength

Unknown, presumed to be the entirety of the species. This includes not only the mundanes but also proto-Initiates, mages and various warmachines, supersoldiers and superweapons developed by those.

Unknown, presumably almost endless ranks of cultists, aberrants and even worse creatures from the Elsewheres. Some texts mention various occult superweapons deployed by the cultists, matching the strength of those deployed by their human opponents.

Casualties

Mankind driven to the verge of extinction multiple times, only for the time itself to be restructured each time to give it one more chance at victory. The last rewrite reduced the effective casualties to zero.

Known casualties include effective death of the Ancient of Malice and death, banishment or sealing of unknown number of aberrants and other supernatural entities.

Objectives

Liberation from the Powers-That-Be.

Suppression and later on extermination of Mankind.