Sagi

was the son of Ōwashi, the twin brother of Toki, and the real heir of the Land of Birds.

Background
Sagi, along with his twin sister, Toki, was born from Ōwashi and an Unnamed Woman.

At some point of his childhood, his mother died.

As a child, Sagi and Toki were very close, and spent much time playing together with their mutual friend Chishima. After his death, his spirit appeared and saved his sister from committing suicide. The spirit gave his sister a pocket watch that had stopped. She swore to avenge her brother's suspicious death and make his frozen time move again, by disguising herself and becoming daimyō in his place to find the one responsible.

Personality
He was very caring to his sister as shown by his spirit in Naruto as well as to the Land of Birds. He seems to value life very much as indicated by the couple of times he used his spirit to save the lives of Naruto and Toki. According to Chishima, he was a cheerful and gentle person.