Warp Fracture Features
Warp fracture features affect the Material Plane in a number of different ways, caused by a number of deities or unnatural laws from other Planes. Causes range from the build up of magical energy in some places, others by either the direct to indirect touch of gods, and others by rare phenomenon & items. One such warping effect is on the physical bodies of organisms caused by the substance known as warpstone. This black greasy stone is effectively matter made up of a mix of condensed magic and energy from either lower planes or planes further outside the known ones. It causes extensive mutation if in direct contact with organic material causing all kinds of weird effects. Extra limbs, strange colours to plants, skin, fur or other body parts. At least to name a few.
Sometimes, a deity or one of it's followers will infuse a portion of itself in a region causing untold warping of both life & region. Hellscapes are usually created this way, and the region becomes a small imprinted version of the being's domain, following it's rules. Time could flow backwards, gravity could work differently, there might be no sound, and any other slight changes. In some though, the effects are quite dramatic. A rare few have the environment & buildings merge with the tissue of living beings creating semi-living buildings, with parts that are made of normal building material, or taking in metallic machine parts with organic material to create biomechanical replicas of buildings, machines, and organisms.
Usually these places are far out of the way, as the natural laws generally don't tolerate the presence of these places. This is especially true in the affected regions that are made here with effectively demonic energy. In many cases the regions are caused by a break or spill-over from another dimension breaking through, and many of them will have a portal of some kind secreted away pouring energies out. Each portal can be sealed though some can be notorious to close. In some cases the deity, or minion, takes a special interest in the region as it allows more of their kind through. In others its the effect of a cult either regularly caring out rituals, set up a portal, contacted a being from beyond, or saturated the region with enough energy to start a warp fracture.
A warp fracture usually takes the for of a portal, though in a very few cases, an actual fracture takes place between different planes that fills the same function. Most beings, and living organisms, generally don't feel at ease in & around these regions, and either avoid it, or look to find some way to stop it.
Manifestation
The laws here are determined by which deity or plane affects the region. Almost all are darkened twisted perversions of what the region should be like.
Localization
Magic, especially summoning type magic, are far easier to carry out in these regions. A presence is usually felt, and the region usually has a number of nightmares affecting locals or travellers passing through.
Type
Metaphysical, Demonic
Oh, I love this idea. Because of its ephemeral nature, I always struggle with ways to explain or even just mention in passing the planes of existence. In my manuscript I created a band of demons from 7 tribes who escaped the lower realms (my generic term for things) because they didn't want to keep fighting. Though all lawful evil, they are true hedonists and as such wanted to live for joy. I call them the 7 Tribes Demons and they've existed in my world on the material plane for a couple of centuries now. I've explained of course, how and why, etc. I didn't mean to write about me, I meant to write about how much I like your concept. I don't think this is an easy subject to write about!
Personally standing on the shoulders of giants here. Inspired by elements of H. P. Lovecraft, & parts of the Warhammer lore about Chaos, to be honest. Think you would like the latter for their god Slaanesh, haha. Very hedonistic, especially the earlier incarnations of him/her/them/it. The only trick I find is to the basic idea down then just flesh it out from there.
I'm basically an idiot. I am working on a re-write of a novel and didn't see the point of world building. I mean, DUH. But on a whim I started doing those prompts (I hope they count...I never pledged or anything) and lo and behold, things I hadn't quite figured out how to deal with in my manuscript were laying at my feet like manna fallen from the sky. I never even related world building to writing novels even though I'm sitting here looking at the 12 books that Tolkien published about Middle Earth. I'm sleep deprived, giddy with gladness and I have a game of Sinking City tonight (Cthulu based D&D game). I'm having the time of my life. And enjoying the discovery of fantastic worlds like yours.
Think I've heard of Sinking City, just can't remember where. Tolkien sure spent the time on world building. Helped that he was an expert in his field of languages & history of the Germanic world & languages. The trick I find about the world building is to stick down just enough for prompts when needed, and if you can add a bit more, or an alternative take on a subject too. Doesn't have to be much, just enough to to be expanded if necessary, and use the rest at a different time. Makes life much more easy. The prompts can be useful, I agree with you. Helps when something is overlooked or needing expanded upon. Get some sleep before you game, so Cthulhu doesn't visit, haha. And enjoy the game.
Every week, I am positive that my aberrant soul sorcerer from Eberon will die. I believe I may be the only PC who hasn't died at least once. If I have to make a new character now though, it will be incredibly difficult. I chose to play the character as a man just balanced on the razor edge of insanity going into this game for a reason. Solan believes that he is responsible for the Mourning (the destruction of Cyre) and in fact, he may be just that. Because he came to Innsmouth paranoid and guilty, I thought it might help him stay somewhat removed from the immediate danger and paranoia that he *should* be feeling. But yes, I must sleep. Thanks!
For anything involving Cthulhu, you need a bit of insanity. only way to survive. Especially around Innsmouth. One of my all time favourite Lovecraft stories that, A Shadow Over Innsmouth.
Ah, you said exactly what I intuitively felt about creating the character for Sinking City. I've just read all of Lovecraft's Cthulhu stories concerning Innsmouth in the last year and loved them but can't remember which one you mentioned as your favorite. I have the book 3 feet away but it's precariously balanced in the middle of a great stack of books that includes "Beowulf and the Critics," by J.R.R. Tolkien. I sell antiquarian, rare and used books for a living but there are some books I can't bear to see leave my possession.
Can't really say that I have one favourite story of his overall. Reread them all a couple of years ago when I got the hardback book called Necronomicon, with all his stories in it. Took ages to read just the shear size of it, but enjoyable all the same. Must come across some real treats there selling those types of books.. Like I've said to others, about a quarter of my favourite stories & books were wrote by people who are deceased.