Dooming the world

[Sheogoroth]

Hmmm...
I'm having difficulty framing my question so please bear with me.

So me and some friends have a Kingmaker Campaign running with grand aspirations and so on and so forth.
My DM likes to run a persistent world across campaigns, which takes a lot of work on his part is actually really cool.

He has also hinted that if we piss off them off enough, Brevoy will wipe us out.

So I had the idea to almost summon an Elder Evil.
Here's my question: is there an Elder Evil or roughly equivalent big bad that I can get to the very last stage of summoning and then hold it there as a mutually assured weapon of mass self-destruction button in case we get wiped out?

Thanks!

[Chilingsworth]

What's your world's geography like? Does everything take place on a single continental mass? What's the climate?

If the world area you want to devestate stays above -20 F, and is a single landmass, you could mess it up pretty good with a brown mold bomb. (i.e. get one square of brown mold on the surface, then repeatedly hit it with fire damage, causing it to repeatedly double in size. 100 times gives an area of brown mold much larger than the surface area of the earth.) Down side is that all it takes is one point of cold damage to kill all the brown mold off. Still, you might be able to get away with packing a bunch of mold in with 100 flasks of alchemist's fire. Drop the package and brown mold instantly covers everything. Otherwise, you'll have to drop the alchemist's fire one flask at a time.

(EDIT, Sorry for the text wall.)

[Sheogoroth]

Not what I was had in mind, but a very elegant solution nonetheless.
That's a perfectly controlled environment, though.

I'll keep that one in mind, anything specifically to do with Elder Evils or doomsday kind of things?

[Ravens_cry]

Ah, I loved Kingmaker. d20 SimCity and a lot of fun to boot! I didn't like the story, (sorry, Fay and Lewis Carroll have nothing in common to me) but ruling a barony/duchy/kingdom? Awesome!
But seriously, isn't there a better option than Apocalypse? How about a little political assassination instead of becoming a mass murderer of horrific proportions?

[Toy Killer]

This is a quintessential DM question. The process for summoning elder evils is deliberately held as an NPC hand wave due to the fact that, well, NPCs are typically the ones summoning the elder evils and PCs are trying to stop them.

I would, rather then straight ask your DM, make a complicated summoning ritual for you're chosen doomsday device with a, non-time sensitive, trigger that you can threaten to pull at the end. This way, you're DM can approve it, you can go through the ritual process and give him something to work with (I.E. if you need three hundred Giffon talons, he can tell you of the Airbow Griffonry that you can raid for the fresh talons, or what have you), and still not be giving up that you can hold off on the final piece until you've made your demands.

By the way, it sounds like fun!

[Telok]

Craft Wonderous Item feat?

An animated iron swallow or finch enchanted with 2/day autofire Widened Control Weather (hurricane force winds) and Nystul's Magic Aura (nonmagic) will wreck a pretty decent sized area. Plus the winds will move it each time, so the bad weather will slowly "roam" the land. Just one is bad, three dozen is a pretty good WMD, 600 is a world-wide catastrophe.

Make and bottle a few dozen Invisible Spell, Fell Drain, Acid Splash, Living Spells?

[Darth Stabber]

Make and bottle a few dozen Invisible Spell, Fell Drain, Acid Splash, Living Spells?

Change the acid splash to a sonic snap, make roaming brown notes.

[Phelix-Mu]

Monster Manual 5, p16 describes a (pathetically easy) way to Dalmosh, a CR17 unique being from the Abyss. While he isn't really elder evil scale, you could definitely destroy a couple cities with him, and he's very difficult to actually kill, so you can call him over and over (10k gp of fine food/drink each time is surprisingly affordable). The only hard part seems to be the DC47 Knowledge check to know the ritual, which isn't really that hard (and who would have guessed that to summon the Dalmosh of the Infinite Maws would require lots of food...).

Anything much more elaborate is probably gonna require some custom rulings by the DM.

You could start some kind of suicide/death cult, though, and use the souls of those involved to power some kind of grand deal with a demon prince or archduke of hell. Demonic armies have been summoned for much less, for sure. This might require some epic Diplomacy checks, to induce the Zealot npc attitude (Epic Level Handbook) (which your DM would be wise to require that you need to be epic level to achieve). Again, largely down to DM interpretation.