'Shaitan' ..... Arabic word that means 'opponent' in meaning of the word 'enemy'. Reduced tot the well-known word 'Satan'. Why an Arabic word?
Because the Catholic Church hated the religions other than their own and the community of the moslim religion was bigger in numbers.
The Catholic Church used 'Shaitan' against their most dangerous opponent: The Illuminati. Why? Because the doctrine of the Catholic religion and it's power. Scientists doubted the Catholic doctrine for very good reasons. Galileo was captured for that reason. He stated that the Sun was the center of our solar system. The Catholic Church/Vatican was afraid to loose power. Scientists created a secret society 'Illuminatii' which means 'Enlighted'. So the dirty war from the Vatican against the Illuminatii began. And it will going on as long as the Catholic Church want to hold on to it's power.