I always tell people who mention the Illuminati to read about Golden Dawn which was real and a more interesting subject, in my opinion.
If the Illuminati was/is real (aside from the historical one), there is so much stupid stuff out there posted by high school and college kids that the word is meaningless. It's just a jumble of syncretistic nonsense, good luck to anyone deciphering any meaning aside from either putting on a tinfoil hat and committing to conspiracy theories.
The Isis cults go back pretty far, too, though I don't think there is a single continuous one.