Oh yeah, they have no shot at redemption like we do, so that’s one part of the desire for vengeance/anger. But apart from that, the way I’ve come to understand it (and if you’ve ever seen much deliverances, you’d know what I’m talking about), they still have the wants/impulses that they had when they actually had physical bodies…but without a physical body of their own, they have no way to satiate those desires..so imagine being an alcoholic and never being able to drink..or a sex addict and never being able to have sex..which is why they desire to possess or piggyback off of a willing human since it allows them to satiate those desires in the only way possible for them at this point. As to “who created them”, that’s why I mention Genesis 6 as it describes how they were created. There are basically two views on this, and I am unsure which is correct. One says that they are the offspring of fallen angels and humans. The other view says that they are the offspring of Cain’s descendants and those of Seth in particular..Cain’s line being the degenerate one. So that part I think is rather unclear. But what is clear is that God apparently considers whatever union which resulted in their creation to be unholy, degenerate, and degrading to the genes of his intended creation. Or it may be as simple as fallen angels playing with human genetics in test tubes and creating beings. I certainly don’t put any physical technological capabilities past angelic beings. If you notice with the UFO phenomena, there is certainly a trend where those who claim to have been abducted consistently say that the “aliens” (demonic beings in reality) are obsessed with splicing genes and creating hybrids. So, it falls in line with the biblical account in that regard. Also note that it says that in the last days, it will be as in the days of Noah. Well, look at what was going on then and going on now. Seems about as clear as day to me.