Since the same questions are constantly being asked on this forum, by completely innocent and totally in good-faith people, it has come to my attention that a lot of surely genuinely interested people in Shadowlands lore must have a very short attention span. Or at least, a lack of capacity to suspend their disbelief for the sake of enjoyment.
Therefor, I've taken the time to make this summary, which will surely cover all the basics. Enjoy.