Zardoz

In a dystopian future, Zardoz, a mysterious leader, governs the Brutals, a savage tribe, and sends them to the Vortex to become Immortals. Unbeknownst to the Brutals, Zardoz is actually Arthur, a member of the advanced Eternals, who live in a paradise called the Vortex. The Eternals, who have transcended human limitations, are not immune to disease and sin, and Arthur's mission is to study the Brutals for the Eternals. When a Brutal named Zed accidentally enters the Vortex, the Eternals are faced with the possibility of exposing their supposedly perfect society.