Butanawai
Butanawai (Atayal language: Butanawai/Putauatsui) is an ancestor in Atayal mythology in Taiwan. He became rainbow after his death. Mythology 
In ancient days, there was a hero called Butanawai, who treated his tribe fairly, and the people of his tribe saw him as god. When he was dying, he told his tribe that he would become the Red spirit, and he would appear with Sessappo, the Blue spirit, in  the sky, guarding the descendants. If there is a sound appearing with the rainbow, that is the call from Butanawai. See also 
 Atayal people

Notes 

Atayal culture