I think their dark souls continually reincarnate into the same families over and over again. Their memories haven't been completey wiped before birth like the rest of us so they recall some of past lives. The very high level ones are also privy to spectacular secret medical technology so they don't have to worry about the health problems they inflict on humanity.

Why do you think David Rockefeller is alive and well at 94? Kissinger has to be in his 90s and Evelyn Rothschild is 78, but still travels around the world, has great health and looks more like he is in his 50s.