you really need to read The Apocalypse of Yajnavalkya. it explains all of this and more, and relates it to ancient stories, myths and archaeological stuff that hints at this. i figured at first you maybe had read it but the idea of trading women to spawn these super-soldiers in exchange for their protection (and for sure in the early times they would have still had some of their fancy weapons in addition to these giants), they would teach the skills of manipulation and warfare, and of course part of that cost would have been women and babies to murder for their blood rituals and cannibalism. sometimes the cross-breeds would not have been giants, and those would probably have at some point continued to interbreed and lose the obvious features but would have all the conditioning to condition their children and maintain their power. at some point the pure fallen angel stock dwindled out but they continued their inbreeding program to keep some remnant of their genetics. keep in mind that the non-fallen ones stuck around until 5000 years ago, as evidenced by mention of them in many parts of the old testament, dating back to around 4000BC - this is probably because they needed to continue fighting their fallen kin until there was no more pure bloods left. then it was safe for them to leave, because without their pure genetics they didn't have the overwhelming capacities and their diluted descendants were then trying to rebuild their global empire and it took them all of that time to get to where we are now. this is why they are obsessed with transhumanism and genetic and machine augmentation. they can't get their genetics back. they were exterminated, for good reason. this also means that when the angels return, they aren't really going to be dealing with enemies that have even half the capacity to fight back. i'm sure they will try, and probable have been, i mean, that's probably what Roswell was about. i think that through mechanisms involving what you might call magic, they still retain some power but they are earthbound and haven't got the industrial capacity to get off the planet and that has been actively suppressed. the angels are just waiting for the right time - when whoever they don't take away with them ends up obliterated by the coming global disaster. the angels survived already something like 6 of these cycles, and 12000 years ago their society split in two with teh war in heaven and they had to figure out a plan to completely wipe out their enemies. that's why the wording of many of the prophetic texts of the bible are so grandiose and aggressive. what we suffer with now is probably a fraction of what they were capable of when they were pure breeds.