Who is Sachiko (Sachi) from Sacred Journey of the Peaceful Warrior and what is their importance?

Mama Chia's assistant and pupil in learning the kahuna ways, Sachi appears to be about nine years old, with short, jet-black hair and a beautiful smile. She has learned to cook from her father, Joseph, Socrates' former pupil along with Dan Millman in Berkeley, CA. At age four, Sachi asks her newborn baby brother what God feels like, as she is starting to forget. Sachi cares tenderly for Dan when he arrives, sunburned and dehydrated on Molokai Island, and looks in on him from time to time after he recovers. She introduces him to a grumpy frog, and Dan teaches her to do cartwheels. Dan defends Sachi against bullies in town and nearly get