The entire S.T.A.L.K.E.R series is basically that, except instead of it being fantasy, it's all about Chernobyl turning everything in the surrounding area into monsters.
Again, close but no cigar. S.T.A.L.K.E.R has too much civilization, and besides, I want the Deathland to be more of an area in a larger world. Not just a high-level zone, but a constant hell that even the most powerful characters (or groups thereof) are essentially on a time limit after entering. The actual high-level zone would be the End Of The Line, the last permanent settlement connected to anything before it goes totally savage.
Complete with atmospheric conditions; possibly with a transition gradient around the edges, but generally contained via some sort of magics. It might actually work out well if you have players who tend to go nuts with minmaxing their abilities/equipment/possessions. Sail a galleon beyond the (literal) edges of the earth, then unload their magical moving habitat for Mars exploration...
That doesn't work because there's nothing much out there but raw resources and terrible quality living space. There has to be a very good reason for diving into these suicidal places. Things you aren't going to easily get otherwise. One thought I've had is the ruins of a Sufficiently Advanced civilization that went too far and suffered a total but mostly contained collapse. Most of what they made is incomprehensible, some of it is valuable, a lot of it will try to kill you, a few scant things are all three.
Funny this topic comes up-- for a long while, I've wanted a fantasy story set in a world sorta like mythical Greece blended with mid-to-late 20th century fantasy to create a setting so stereotypical that it's somehow
more interesting.
I've actually been working on a concept and story, surrounding a typical hacky-slashy adventurer wielding a broadsword named Badna, called "the Dragon of the North", but I'm torn between a graphic novel and traditional tale. I can't draw people well at all in close-ups, but a book seems less evocative.
Aha! A comprise: traditional book, but with small illustrations (e.g. 8th-page size images of locations or monsters or sword-swinging) every once in a while.
Sorry for the derail.
As for your, erm, "apocalypse zone" setting, the Sufficiently Advanced civilization idea is the easiest and best to go with, but is also overdone. You could go with it, but you'll need something to set yourself apart from the crowd. You could keep the origin a secret until late game, like Zelda: Wind Waker's deal, or you could go invent signature monsters or races, like countless other fantasy settings (the lava dudes, "tz'haar" or whatever they were called from Runescape and the multitude of exclusive D&D monsters come to mind.) Alternatively, you could have a sort of god-born cataclysm or perhaps just natural conditions (i.e. evolutionary "eat or be eaten" in overdrive, depending on magic levels perhaps a "well of evil") causing a deathzone; you could have a mountain range or ocean separating it from the rest of the world, or have the inhabitants thrive on something only found there. Natural resources could range from mythical ores or stones or wood to a joke where a real material like iron, gold, or perhaps copper is found only there.
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