Immortals are ascended beings, or "Ascended Masters", who cannot die.
In 1960, a black man in Africa was performing miracles equivalent to Jesus of Nazareth. The Illuminati made several attempts to kill him by shooting him and cutting up his body parts. They dispersed his body parts across the world. However, "black Jesus" regenerated and said, "In the future, many others like me will be coming, and you will not be able to stop us."
- Osiris myth on Wikipedia, his death and resurrection