Who is Tei Tetua from Kon-Tiki: Across the Pacific by Raft and what is their importance?

While on a zoological expedition on the island of Fatu Hiva, Thor meets Tei Tetua, a very old man and the last of his tribe. Tei Tetua tells Thor the story of how his people first came to the islands by way of Kon Tiki, a white-skinned, bearded man who is also considered a god. This stimulates Thor's imagination, from which he constructs his hypothesis that South Americans could have sailed rafts to the South Sea Islands at around 500 A.D.