historically it is important to remember that our word demon is derived from the greek daemon which simply meant a spirit, it did not have any good or evil connotations. if you also look at the historical accounts there are many encounters with spirits of all kinds from those that are deliberately malicious, to the simply playful (even dangerously so), to the benevolent. the christian conception is the idea of a demon as being an entity who was once an angel which fell from grace and spreads suffering to humanity. as near as i can tell this most likely comes from egyptian or greek ideas moreso than the hebrew. the kaballah talks of the qlippoth or the world of shells. during the original creation the foundation was unstable and the original tree of life collapsed. this became the foundation for the tree of life we now experience. the qlippoth can be seen as the origin of evil spirits, each sepphora is ruled by a certain spirit and keter in the qlippoth is ruled by lilith for example. however it can also be seen as the source of all evil or the evil inclination in mankind.
the overall idea is that there was an original world in which there was no evil but this world was unstable and collapsed. then the shells of the previous emanations provided the foundation of the current world. the eating of the tree of the knowledge of good and evil can be seen to be a metaphor for not just an awakening into 3density consciousness but also of the realization of the evil inclination and the good inclination.
in the loo we find that the logos originally did not give free will or have the veil of forgetting in place. however for there to be free will there has to be something to make a choice between. so in the loo we see that logoi started using a conception of service to self in addition to service to others.
now i want to briefly say what the kaballistic definition of an angel is. an angel is a being without free will that has a single purpose and within that purpose its power is perfect and so is its knowledge. there is a saying that for every angel there is a purpose and for every purpose there is but one angel. this means that there cannot be two angels with the same purpose. now why do i bring this up? in the loo ra mentions that our sun is not a being that progresses through densities but exists in all densities. the sun has a purpose which is to create our solar system. the planets are similar beings to the sun. there is another saying in the torah iirc that goes basically, there is an angel for every star in the heavens. so if beings like our sun and planets can exist in all densities and not be subject to the same progression that we are then it is logical to assume the possibility that this is true for other entities as well. these entities could be what are called angels or demons in our literature.
now we also have the subject of thought forms. this phenomena is mentioned by ra in the loo i think several times but i might be wrong. i know he mentions that one of the three kinds of sasquatch or big foot is a thought form. now some occultists believe that demonic phenomena falls into two branches, the first being a thought form and the second a type of lower 4th dimensional entity. a thought form can exist for almost anything. magical work wherein you strongly visualize an object is supposed to create an astral form of the visualized object or a thought form. certain things that are common among people can become collective thought forms. brotherly love is an example of this concept. the strong emotion of feeling of that type is distinct from other types of love. this energy could be called upon in a magical working and some traditions gave these individual energies names to more effectively call upon them.