Who is Atsula from American Gods and what is their importance?

Atsula is a holy woman, who comes to America in 14,000 B.C. She meets with the other leaders of the tribe, and they channel the god Nunyunnini, who tells them there is evil in the land that will cause their deaths. The god tells them to travel towards the sunrise, where they will find a new land. Atsula doesn't believe it, and believes they will die. The tribe journeys over a land bridge, and Atsula dies at the foot of the cliffs into the new world. The tribe prospers for many years, until another tribe in the new world finds them, kills their men, and takes the women and children into their tribe.