The Illuminati have existed for ages now and they are all humans that have enough wealth to create a secret society that holds so much capital that they can literally decide the fate of millions. These are the people who finance revolutions, they also finance the politicians and turn them into their puppets. There are actually a large number of Illuminati who are members of the group, but they have rivalries to see who can finance more projects to continue to grow wealthier.
This is a game that is reserved only to those who have so much money that they can purchase entire corporations and groups of people to perform all kinds of acts of violence and destruction. We had to beat them because they had completely deprived the world of the chance to evolve naturally. The Illuminati sealed the fate of all humans with their quest for power and they had to be eliminated.