Earthbound evils

While demons typically arise within the lower planes (and are largely trapped there), some people are so evil that their souls may become demons without ever leaving the material plane. Likewise, some terrestrial spirits may become so corrupt that they are twisted into demons. Some may build fleshy bodies for themselves or reincarnate within family lineages. These earthbound evils are commonly known by names like div, oni, rakshasa, and sahkil depending on the local culture. Pathfinder introduces all of these as new races of demons, but I prefer not to split hairs. The rakshasa and ogre mage in the MM are examples of such demons, but they come in many more varieties (see the PF bestiaries for ideas and then build them using the DMG guidelines).

Fantasy space travel primer

At I explained previously, one of the key changes in my cosmology is merging the Ethereal, Astral and Faerie planes. Furthermore, this plane serves a dual role as outer space: space travel may allow travelers to visit other planes as though they were planets or islands on the sea!

The Material Plane

The Material Plane is, for most campaigns, the primary (and often only) setting of the party's adventures. The basic structure of the plane should be family to most adventurers.

The Material plane consists (usually) of a nigh-infinite vacuum, in which float countless galaxies made of countless suns. Many suns are orbited by planets, and some of these planets support life. The most common form of life are "demikind" like humans, elves, dwarves, halflings, and so forth alongside "beastmen" like orcs, gnolls, goblinoids, lizardfolk, and so forth.

While most solar systems are heliocentric, some are geocentric. While most planets are solid aside from underground tunnels, others are hollow and may even contain concentric shells or a miniature sun! Some planets made be composed largely of water or gases. Others may consist of a series of massive asteroids in a stable orbit, where airships are a common means of travel.

Travel between systems is accomplished through gates or flying machines. Beware! In the black void between worlds exists countless unimaginable horrors and alien threats constantly yearning to make planetfall. Possessors, phrenic scourges, formians, ravin, pirates... Thankfully, the threat is mitigated by the presence of stellar empires dedicated to enforcing their own visions of order on the cosmos. Better the devil you know...

For more detailed information on space opera and scifi horror, please refer to such works as Aether & Flux: Sailing the Traverse, Necropunk Campaign Setting, Between Chains and Starlight, Dragonstar: Starfarer's Handbook, Voidspanners, It Came From The Stars: Campaign Guide, et al.

The Material Plane is encircled by the Vault of Stars, otherwise known as the night sky. A massive surface made of an unknown black material, the Vault is the plane of moral neutrality. It is home to the star pools, fey, aeons, psychopomps and many other strange entities. For more detailed information on the Vault of Stars, please refer to Classic Play: The Book of the Planes.