Highlander: The Series (1992) : 4x13

The Immortal Coltec is a Native American Hayoka -- a shaman whose responsibility is to take evil into himself to protect his people. After the massacre of MacLeod's Indian family in 1872, Coltec saved MacLeod by taking in the evil and rage he felt. Since the death of his tribe, Coltec has become Hayoka to the world, protecting it from evil Immortals. But Coltec's capacity for evil isn't endless and when evil finally overtakes hin, MacLeod must find a way to save Coltec without being drawn into the evil himself.