Okay, looking back at what I wrote, there are big spoilers in here, probably. Not much of this is said beyond exposition in the End of the Beginning itself, but it's worth noting since the vague question means that I can go on at length about continuity, which I love.
I'm not entirely certain how it started, but it's essentially a continuation of the histories of the Protectors that Huinesoron and some older, now-inactive writers made back around 2006 or so. The End of the Beginning builds off of the Ten Years Hence idea that writers of early and/or influential spin-offs liked to do to show their agents in new periods of time as older and occasionally wiser versions of themselves for character purposes. Huinesoron uses the format to create a theoretical future that would map out the families of the characters from his old DOGA spin-off. I'm not entirely sure how the idea for the Department of Efficiency came about, but it provided a founding reason to change up the possible future in a big way so that it wasn't just a story about brief moments in the lives of characters we've rarely if ever seen before.
Now, DE history and potential spoilers follow: a group of Floaters headed by an obscure Flower known as the Foxglove(not to be confused with the Foxglove Official of the All-Purpose Department in the same way that the Marquis de Sod is not to be confused with the Daisy) decided to create a way to increase the productivity of the PPC; it was a fine idea at first, but the DE began to abuse its power, imposing mandatory and occasionally arbitrary rules on most of the organization in the name of efficiency, but in effect using their semi-monopolistic power as a handhold to seize control of the Protectors.
Eventually, the Department of Efficiency allied with a resurrected version of the Department of Author Correspondence, one of the dead Departments from the early spin-offs, which quickly became the corrupt and sadistic Department of Author Correction, headed by the Cherry Tree(who had/has not been seen before or since, by the way), and Something Bad Happened. It's not been shown what it was, but it involved the capture and torture of people from World One on the order of the Cherry Tree and supported by the DE.
The Crocus, Head of the old-spin-off-era Department of Author Correspondence(which had basically been DMS-light, for reference) now Head of Operations, teamed up with the Sub Rosa, the Last of the Firstborn, and started a war against the DE-sympathizing Flowers. The DAC was driven out, and the DE was almost completely purged, but since the latter had ingrained itself in just about every aspect of PPC workings by the time of the war, its destruction caused several Departments to split into factions, while the Protectors developed extensive rivalries with other groups, leading the grounds for the factions and Departments going separate ways.
The Sub Rosa resigned, and she, her surviving sympathizers(no word on whether the Crocus survived as well), and an unknown number of followers retreated elsewhere in the multiverse, leading to all but a select group of the fragmented PPC to abandon HQ. As to what the Sundering is, it could be either the Flower-versus-Flower civil war, the fragmentation of the Department cohesiveness, or the abandonment of HQ; I'm not sure which.
The last story, the Seventy Years on period, deals with the Paladins, an alliance of former factions of DMS, DBS, and DOGA, and the Rangers, the remnants of Intel. They had decided during the unrecorded time span to team up and kill Sues like their ancestors did, and this led to the Time Will Decide For Us story, which isn't finished, and the Door To The Future RP, which pollinated the Twisted Skein Alternate Multiverse(actually, since the Twisted Skein hosts two alternate multiverses, I'll just call it the Sundering alternate multiverse after this post) with the undesignated "prime" multiverse, giving the former some of the lost technology of the latter and, as of Trousers of Time, preventing the latter from effectively becoming the former.
Actually I'm excited about the new development and the full-on confirmation that the Sundering took place in an alternate multiverse. Now that the world that underwent the Sundering is no longer "the real future", it's not going to be the bare-bones world it made itself to keep from stepping on the toes of future writers. That means we can write in the Seventy Years on time period now! Again, I'm excited. I've got some good ideas on some other factions and such, and there's a plot thread that hasn't been touched since 2008(real time, not AU time) that I've been dying to pick up ever since I found out about it.
