Guren Hibana was born on August 12 as the first born son of Satō and Yōgan since the birth took five days he was supposed to be born on the 7th. He was very cautious to not fall off the Todoroki Volcano even though his father had met his mother because he did.
The Birth of Hidan
He was very comforting to his mother while she gave birth to his younger brother which also took five days like Guren's did.
Death of Guren
He was Killed In Action or KIA at age twenty and his brother wanted revenge but Satō and Yōgan were afraid that they would lose their other son too. Some say that he was trying to save a girl named Yume Hakasan.
Guren was a sweet and kind young boy, he would always help animals and people in need. When he grew older, he was found spending a lot of time with Yume.