I certainly believe in the Illuminati but it's not really one group of individuals with intentions of secretly ruling the world, although it makes for a great story. The Illuminati to me is actually just what we have come to call a bunch of different organizations and secret societies like the Masons Skull and Bones. These groups originated hundreds of years ago with much of their history shrouded in history. Today's Freemasons for instance originated during the the dark ages. Many believe they secreted the arc of the covenant out of the second temple in Isreal when it was destroyed.
My point is that groups like the Masons, Bones, Shriners etc have always had stories about them that has made people uncertain of whether they're really the good guys. It doesnt help that keeping everything a secret is part of the deal. In addition to these types of groups, I also include some political groups like those that make up the US deep state or shadow government as a part of the Illuminati. In politics, there's a lot of invisible propaganda being thrown at people in an attempt to control the minds and actions of society. It is very much something people attribute to the Illuminati.
I cant leave out the multi-billionaires that head up huge cooperations. As part of the Bilderberg Group along with about 250 of the worlds so called elite from finance, business and politics have been meeting pretty much secret since the 50's. They do not disclose locations or topics discussed with the rest of the world.
Many of the people that I'm talking about are known to practice a philosophy and way of life that goes all the way back to early ancient Egypt. Called the Hermetic Principle, making them all very like minded. The law of attraction is a very deep, odd theory that is widely but quietly believed and practiced among the Illuminati.