I was writing a post about a timekeeping technique called Time Bubbling (coming soon!), and I realised that there was a worldbuilding technique that I think is essential to most fantasy worlds that we play treasure-hunting in: Apocalypsing. Don’t worry, this one will be a quick one.

Most D&D-likes are post-apocalyptic. When you’re world-building, the first thing you need to decide is: What was your apocalypse, and what were its consequences? Because this is a fun question to ask, and it says a lot about your world.
The size of an apocalypse
The main decision you need to make about your apocalypse is whether is was a local apocalypse or a global one. A local apocalypse might look like this:
The kingdom of Magras was once a noble kingdom well-known for its Oogrish stonework and its advances in automation. It was destroyed in a war with the Moondark Queen, and now only remnants remain in a twisted wilderness peppered with the ruins of the old kingdom and cultists of the now-dead Moondark Queen.
Whereas a global apocalypse might look like this:
One thousand years ago the God-priestess of Som Nam used her secret and blasphemous arcane research to open a hole between the mundane and the eldest divinity, allowing the divine to engulf and infect the world. The portal was wedged closed by a consortium of long-dead knights, however not before the world was shattered by the destruction caused by Darkness of Possession, the Devouring Void, and the Ecstasy of Destruction. Were these three elder gods ever truly vanquished?
Choosing which sized apocalypse you want to write about is more important than the nature of that apocalypse, because it will often dictate the nature of your campaign and how much sense treasure-hunting makes in that context.
The nature of your apocalypse
The nature of your apocalypse helps dictate what kind of hazards might be encountered, what kind of treasure there might be, and what kind of community remains.
Our two earlier apocalypses were military and divine in nature respectively, but there are many opportunities for other apocalypses such as war, famine, climate change, the summoning death-gods, causing divine wrath, creating intelligences that turn upon you, accidentally merging your dimension with another dimension, mountains falling from the sky, or an army of sorcerers suddenly trying on each ther because their access to magic was tainted.
Choosing the nature of your apocalypse is less important than the consequence that that apocalypse has on the world now. The nature of the apocalypse is just lore. Don’t put too much thought into it.
Fun apocalypse consequences and tensions
Instead focus on the consequences of the apocalypse and the tensions it causes. Let’s take our two earlier apocalypses.
In the first, the war has left only a remnant: Let’s say there are the remnants of the militant nobles, now solitary but organised and patrolling the wilderness to protect the most sacred object of Magras, the remnants of the innocent civilians, reduced to subsistence in walled villages or living in caves, and the remnants of the cultists, in the desecrated temples of the past empire. In the ruins are automated technologies that only need to be activated or repaired to be implemented. Outside of Magras, there are likely places unaffected by the war who have an interest in the technology of Magras, and who are in opposition to the Rangers and may ally with the cultists or the remaining magrasians in exchange for passage or information.
In the second, a thousand years have passed, but there are wastelands that new communities and old have had to learn to avoid and overcome. There are zombie wastelands of the Possessed, there are whirlpools and black holes rendering swathes of land uninhabitable by the Void, and roving bands of the crazed devotees to the Ecstasy of Destruction roam the lands chaotically. There is a mystery here, too: Is this all still remaining, or are the elder gods still here and biding their time?
Consequences can also be mechanical: Time is broken, and now different groups travel in different timelines. Magical artefacts are rogue, and now they must be tamed. Violence was banished, and now combat can only occur in certain arenas. The benevolent gods fled, and now the only gods hide their curses behind blessings.
Note how tensions are harder to extract from a thousand-year-old apocalypse. Easier to extract treasure, or hazards, or enemies that have been trapped or held in stasis. But having elder gods hibernating beneath the land is cool! How do we bridge the two?
Layered apocalypses
Well, we layer apocalypses. We can have our thousand-year elder god apocalypse, our recent war with the Moondark-Queen, and the kingdom that stood on the same ground that was destroyed 500 years ago by its hubris in attempting to harness the power of prism-batteries.
There is a danger in layering apocalypses, however, because the more we layer apocalypses, the more we need to explain why the previous apocalypse hasn’t been demolished and looted. This can be fruitful, though: Stone is expensive to mine, so if there is stonework it’s likely to be repurposed. What does this look like in modern or pre-modern architecture? Did they respect the ancients and preserve it? Treasure is likely to be taken unless it’s dangerous. Most communities will mark danger with signs that are meant to be universal (see physical waste markers). What are these signs? How did subsequent communities use the treasure or the technology they found that was not dangerous? Why are there no dinosaur skeletons? Why are the ruins beneath the ground? Did they live in dungeons, or did the apocalypse bury them? Ask these questions, these are the fun questions to ask, that will bring weirdness to your world.
That’s it, really. Let me know your thoughts, and tell me about your apocalypses!
Addendum: Mechanical consequences was added to the consequence section.
2nd February 2023,
Idle Cartulary