Demons, creatures of inmense evil and destruction incarnate. There area lot of legends about them and all of them portrait them as enemies of all its dear to someone.
Demons say that the universe was previously the Hakru, literally void in their tongue, calling the current universe Dara, or world. No mortal erudite could even comprehend what the Hakru actually is. Demons say that not even Dara-born demons can actually undertand it properly. Only Old Demons can properly understand it.
There are very few Old Demons and all want to return to the Hakru, and to do it, corrupting and destroying the Daa is required... how they will achieve it? No one knows. No one can understand Old Demons plans. Old Demons are unique and powerful demons, including demon gods like Angra, Belphegor, Iblis and Astaroth, with strange forms. Then came the Middle Demons, hakru-born demons but adapted to Dara, giving them unique but more mundane forms, including demon gods like: Yatan, Nagrioth, Akuma, Azzoïl and the Deep One. New demons are mass produced, dara-born and often weaker, designed as corruptors and shook troops.
Demon soul is diferent than any Dara soul, as it comes from the Hakru. As Hakru is no more, these souls are limited in supply. They can be recicled but being insuficient they created substitutes: corrupted Dara souls, or, better said, mortals corrupted enough to be able to be reincarnated into a demon. Another component is the infernal energy, remnant of the Hakru, it cannot be recycled and if a demon dies its lost. But it can be generated from mortal negative emotions like suffering and hate, if a demon produces more energy because of the emotions they caused with their actions before dying, then its life was woth it for their masters. The more infernal energy invested in their creation, the more powerful, so a worthful demon could be reborn with more energy and then, more powerful a useless one, could be reborn with less energy.
There's a prohibition about wich souls can be corrupted, dragon souls are forebidden, as a corrupt dragon soul is very dangerous, as they tend to suck all the infernal energy they have aviable, becoming very powerful and rampaging eating demons if they don't have enough energy. Even demon gods fear such a rampaging beast.
Civilization and Culture
Infernal names, they vary a lot
Demon gods, of course
Demon or Devil tracks, some with Abomination