Drift
It's a rare disease of the mind, the Healers say, likely made worse by the desert magic, the Jewel and his own Gift combining in unforeseeable ways. The Bazhir deny that the Voice of the Tribes was ever meant for a foreigner.
It's small things at first. Day to day details start to elude him, though he can recall every stride of the race for the Chieftaincy (a rite long abandoned) with crystalline clarity. He calls his children by the names of centuries-dead Bazhir. He stops recognizing familiar faces. The words of his language are replaced with the tribal tongue.
Eventually his mind is wholly claimed by the past; remembered lives like specks of sand—thousands, millions, an infinite desert—sweep over him until he is gone.