Bonjii is a character in the twentieth Pocket Monsters movie. He is a researcher who has spent many years of his life chasing after the Legendary Houou. He is known to have written a book titled "My Life is Houou". During the movie, he will help Satoshi, Makoto, and Souji on their adventure towards Mount Tensei, where Houou lives.
(Source: Bulbapedia, edited)