Project Nemesis is a fan driven website for games that use the One-Roll Engine (like Nemesis, Wild Talents, Reign and Monsters) or Chaosium's Basic Roleplay System (BRP) (like Call of Cthulhu) and the Delta Green setting.
The EndTimes were set into motion by World War One, the Great
Depression, and (especially) World War Two. These events reshaped and
changed the face of our world forever. For the mythos-related forces,
these times were critical.
As the stars began to come right the influence of the GOOs/OGs became more pronounced, subtly influencing humanity's path. The lesser mythos races started undergoing changes, some becoming extinct or departing Earth (such as the Sand Dwellers or Lliogor) and some changing tactics (like the Mi-Go). The old cults began to adapt to the changing times or died on the vine. This was the reason for the sudden surge in mythos activity during this time. You had the clash of the old ways with the new times, something mirrored in both mankind and mythos. When everything had cleared, you had new orders in both arenas. This was the signal of the coming times.
The great events of the first half of the 20th century set the stage for the time we live in now, a time I call the EndTimes Prelude. We are witnessing the prophecies of Lovecraft coming to fruition. Runaway Nationalism makes us more insular and war-like. Technology is pushing us to be more than human, "improving" ourselves. We pollute and deforest and all the lovely things the Delta Green book outlines that are leading us towards our extinction. The mythos forces are organizing and banding together, as we see with Tiger Transit allying with the Fate which is working with the Karotechia (and in essence led by the same entity) and so on.
Thousands are flocking to mythos fronts. Those groups that prosper and grow find themselves drawn towards the larger, established groups, increasing their power further. Those that don't make it, still serve a purpose for spreading chaos (sort of a twist on the guerrilla concept of "let a thousand flowers bloom"). We will continue to "progress" as we push ourselves into the abyss but this plan isn't simply for our destruction. Every act we play out has some importance to the return of the GOO/OGs. That's the part we play, the cults play and why that meddler, Nyarly, interacts. Our destruction is secondary and would come simply with the return. The part we play out is to pave that way and make it easier for the GOOs when they wake up. We are like a maid service for the GOOs. We aren't needed and we are largely unnoticed but the things we do make it a little more comfortable in the end. We give wake-up calls (those summoning spells and the way those cultists are always trying to tear down those pesky prison barriers), warm up the room (greenhouse effect makes things warmer and changes the atmosphere to be a bit like it was before when the GOOs were awake…after all, wouldn't want Cthulhu catching an annoying chill), put the house in order (nice of us to move slumbering deities around and gather artifacts in convenient places for when they get home) and so on. And like a good maid service, we do it while they are out and then disappear.
Now I see all of this coming to head for the 2030s part of the Endtimes timeline. We will have reached a "cyberpunk" future: dirty, gritty and where life is cheap while we are surrounded by the greatest of (human) technological marvels. We will have become fierce and territorial, fighting for our mega-corp masters or the shattered remnants of the nation-states. Nyarly will have completed the creation of his uber-cult, pulling together the elements of the Fate, Karotechia, COT, Tiger Transit and so on. He will rule behind the scenes through an occult elite, who in turn will run thousands of fronts (many quite mundane but still adding to the overall power and influence of the human-mythos alliance).
The barriers of the GOOs/OGs will then begin crumbling. I don't see this as a sudden, one-day event. Instead, an ever-increasing level of "strange" activities will begin to signal the apocalypse (and provide some great gaming). Disasters will erupt. You will see DO hybrids changing quickly and running amok. The dead start to rise under the control of cult necromancers. Ships are sunk by waking star-spawn. Humanity will fight back but between the "unusual" forces of the mythos and the activities of the cultist fifth column, we will be pushed back. News reports will cover the valiant siege of Boston against the Deep Ones or the attack on London by star Spawn.
Then, one by one, the GOOs will return. Between the wars and disasters and the effects of their return, billions will die and the Earth will be reshaped more to their liking. I still don't see this as the complete extinction, however. Some will simply escape the planet, taking their chances in the stars. Many will be grabbed up by the Mi-Go for their purposes. Many will retreat to small enclaves, fighting for simple survival against the other survivors, driven at least half-mad by events. The Deep Ones will probably set up prison breeding camps for humans they capture to continue their species. Finally, those who were loyal to the GOO/OGs (such as the immortal Chinese masters of Cthulhu and some of the followers of Nyarly) will get their "reward" for services rendered, allowed to live and rule their own small empires. These are nothing more than enclaves on a blasted Earth but beggars can't be choosers. They are immortal in the way DOs are, hence violence can kill them (and they are a violent lot). These all then will begin to represent the far-future empires discussed and the divergent branches of humanity. Each "branch" is changing (or being changed) to be something different from what we are now. Eventually, humanity will either become extinct or be absorbed into other species, ending mankind.
A final item I like to use is that many of the survivors who aren't assimilated by something else are what eventually devolve to become the coleopterans of the future. That's why the Great Race has an interest in us. They are neither benevolent nor malevolent, but instead seek to both follow the evolutionary changes that will take place in us (to better understand what they will be in the future) and to ensure that the change takes place. They are here to stop any premature extinction, push biotechnology through and so on to subtly provide for their survival and future. To us, they can be allies sometimes and enemies at others. To them, they are simply scientists following a grand experiment.