Author's Note: Nothing on this page is set in stone yet, it's all just my personal ideas free to be edited by anyone.
The Fourth Fansus used to be two different Mansi, independent of one another, each inhabited by a different group of Gods-from-Stone and each with their own Glory. These Gods-from-Stone warred among each other, in a war whose ending has been lost to time. The twin Mansi were desolate, war-torn wrecks when the first Hours of Humankind awoke, as were the Gods-from-Stone who inhabited them. The new Hours either killed them or in other ways usurped the Gods-from-Stone (Perhaps different approaches in each Mansus) and sent them to Nowhere. Everything seemed cool and good and the new Hours rebuilt the two Mansi but remained on separate terms most likely due to disagreements of some sort (maybe about the war and its ending). Eventually, though, something super fucked up happened. The 2 Mansi crashed into each other, and nobody knew who was responsible. Did the Gods-from-Stone do it all the way from Nowhere? Did someone from within the Houses do it? Or something else entirely? Who the hell knows.
What is known is that this was a horrific event for humans and Hours alike, with the 2 Glories colliding and breaking apart. This, combined with the damage the Hours suffered, temporarily broke down the barrier between realities and released the power the Hours bled into the waking world, where it caused unspeakable devastation. Most of what occurred in that devastating time when all hell broke loose has been forgotten but what is known has been recorded below:
The Collision
See: The Collision