Invaders of Xor

Xor is a living world of meat, plunder and wonder
A ever living mystery and world eater
People live on and in Xor like parasites
Bad things come from other worlds
Things not good to eat that must die
Strangers who do not accept the will of Xor!

All kinds of otherworlds invade Xor for a meal which has the danger Xor might flood that dimension. Xor only wants to peacefully eat universes and barley is aware of intruders parasitism. But look out when Xor does notice your dimension and is hungry. Some otherworlders are stranded here and join a community or start one. Parts of otherworlds might be found inside of Xor taking thousands of years to be assimilated. Xor might even be used as a nexus between worlds but a dangerous one. Bringing goods through the gates and leaving on both sides makes the worlds interconnected. Creatures of law may not be approving of Xor and consider it close to chaos or raw material for chaos to usurp. Invaders of Law act poorly and are often disliked by xorians unless they actually fight need someone to fight chaos.

One of  these in a region will stand out and provide threats aplenty. Why not start between two of these or one at each compass point. Intruders usually have a way home but that might be be at a certain place or require a relic. Intruder gateways are for outright alien plunderers or explorers. Strange remnants are a place where unnatural to the nature of Xor creatures come from, a remnant of the past or otherworldly infection.

d12 Intruder gateways into Xor
1 Primal Law - entities such as Archons come to hunt and destroy chaos and imperfection
2 Singularity - bastion of Law where crusaders wage war against chaos and disorder
3 Deadworld - land smothered by darkness and necromancy and the hungry dead
4 Dungeonworld - a infinite self aware dungeon complex linked to the hells
5 Garbageworld - covered in garbage from other planes, locals seek to escape
6 Planet Psychon - mutants, androids, robots stumble on gateways
7 Europe 1640 - England and Spain search for new worlds while secret wizards planeshift*
8 Ancient Exilon - bronze age ancient city states send adventurers to visit Xor
9 Shadelport - city of pirates and wizards and elder ruins, many gates remain from long ago when the Monster Kings ruled and used to raid and plunder Xor
10 Underland - various races of the deep raid Xor for food and some worship it
11 Demonic chaos - seeks to corrupt Xor into becoming a home for demon kind
12 Primal chaos - swarms of gelatinous tentacled alien horrors

*Other times are possible like modern special forces or monster investigators

d12 Strange remnants within Xor
1  Mile wide clod of earth with some intact ruined settlement survivors from some other world, semi buried intact ruins are their current lain and they are just exploring xor
2 Mass of ship hulks and a sargassum of weed fused into a mass inhabited by sailors from many worlds and a few feisty sea monsters surviving. Sailors are damned and don't try to escape
3 Collosal mass of fungus caverns inhabited by fungus and faerie folk, including by goblinoids, pixies, elves, gnomes, mushroom people, giant bugs and more 
4 Dead area where a necromancer lives and has learned to make undead from the dead flesh of Xor. If not stopped many such places grow. Some are quiet and hidden for aeons
5 A large section of a underland city was snatched and relocated inside Xor and inhabitants have done well and trade with the locals. Many strange races are among survivors
6 Macroscopic life has infested the area attacking and feasting on Xor and spreading it's own single celled life forms colonies, some are individually baseball or beachball sized often linked in chains. Dangerous slimes, jellies, flagellum and strange life thrives
7 Bone castle once a living place housing a population now a desolate dead hollow, full of all kinds of unwholesome creatures and cults in the skeleton of a living citadel
8 Infected sickly swamp of putrid sweat, infections and ulcers form a unique environment, disgusting but welcoming to bugs and the goblins who hunt them. Demons and undead here prevent the land being healed 
9 Crystalline life form ecology is absorbing life and fluid, growing and expanding into complex alien intelligences. Psionic beings have been attracted or empowered and come here
10 Dragonspawn Pits of Tiamat, mother of dragons has opened a gate here where thousands of baby dragons are fattening up on Xor for the next dragon apocalypse on some dimension. Tiamat only pops in occasionally 1in6. Xor does not mind dragons as they excrete his spoor on distant dimensions aiding it
11 Chaos warp point where creatures become mutated and prepare to  kidnap and devour nearby peoples. 
12 Chaos infection where a demon throne of a abyssal lord festers with it's horde. With intent to conquer the local area, warbands rair the surroundings often meeting Templars of Xor or Crusaders of Xor or many other local forces waging eternal war

Terrible new theory:
Humans came from Xor first
Then spread to other worlds