Demons

And there he stood, the man I once loved. Now nothing but an emotionless husk, black smoke billowing from his eyes. That leathery, weathered face that was once so full of kindness, now an emotionless mask. How could this be anything but the purest form of evil?

— Unknown source

Description

Despite their horrible reputation demons are not inherently evil per se, at least not by their standards. And it is true that in terms of morality they are sort of neutral, operating almost solely based on survival instinct. How unfortunate it is for other species then, that their souls are the demon's lifeblood.

Origin

Why demons are formed is unclear, but how they are born is known. Usually they are the product of a corrupted soul being in the presence of an equally blackened source of energy. They are initially formed as a shadowy mass that eventually takes on a feral demonic shape. The size and strength of this form depend on the power of the soul or the amount of energy expended when they were formed. Regardless they are all initially mindless creatures, until they consume a living creature's soul that is. At that point they start to obtain intelligence and individuality, as they learn from the memories of the souls they have consumed. The first few souls they consume tend to have a significant amount of influence on their eventual personality and they can even assume the form of the soul that resonates most with them. These humanoid forms however are limiting and to access their true power they have to revert back to their demonic form. As they grow stronger, demons need more and more souls to sustain their forms, which is why some demons choose to shed some of their excess energy, which can form into a new demon as well.
One important distinction between naturally formed and created demons is in their name. A demon that is created by another demon shedding excess energy is given its True Name by the demon that created it and is thus bound to serve them loyally. Demons that are formed naturally attain their True Name when they achieve intelligence. This name can be anything and the demon knows it instinctively, but it is usually tied to the memories of the dominant soul (but not the same as that of the dominant soul).

Personality

Their need to consume souls is why they are branded as evil by nearly all sentient humanoid species. It is also why they are generally hunted down once their presence is found out. Younger demons especially tend to go on a warpath to amass more souls and thus more power, but they rarely survive long enough to amount to anything. Elder demons however are quite experienced and more subtle as to how they amass the souls they require. They bargain with people, make contracts and trick them into giving up their souls willingly. The Archdemons, the most powerful of their kind, are almost unequivocally power-hungry and some of the most evil individuals of their kind, considering how they remorselessly do everything to amass as many souls as they can to increase their own power.
Several of the intelligent elder demons have grown tired of the endless cycle of consumption and have been experimenting on souls to find a solution. Though playing with stolen souls is cruel in its own way as well. Some of the more pacifistic demons try to subsist purely on animal souls, reasoning that those are less likely to strike back.

Basic Information

Dietary Needs and Habits

Persist solely on souls. Depending on their size and strength the amount they need can vary from only one soul per year to a soul per day.

Morality and Personality

While most demons do not necessarily consider themselves evil, it should be pointed out that their sense of morality is rather different from that of most civilized species. They come into this world with no frame of reference, and when they consume their first souls they take over the feelings and memories, but without the experience of having lived in society for years. Thus they might take any strong feelings or convictions of the consumed as the standard, which can lead to them taking thoughts to an extreme. For example a newly born demon may consume the soul of a man whose wife cheated on him, and who holds a large amount of resentment for that. The demon would assume this anger and consider it so wrong that it will kill the (ex-)wife. Furthermore it may start to believe that anyone who would break a bond of trust with another deserves to die, and considering how general this stance is, it could very well go on a slaughter spree. Now this is not to say that this is always the case, many demons often do things that they know are perceived to be wrong just like many humans would. However, the difference in moral values is quite common among demons.