Bonjii appears in the twentieth Pocket Monsters film as a researcher obsessed with tracking down the legendary Houou. He's spent basically his whole life chasing after this Pokémon, which says something about his dedication—or maybe his stubbornness. He even wrote a book about it called "My Life is Houou," which is pretty on-the-nose if you ask fans.
During the movie, he ends up helping Satoshi, Makoto, and Souji make their way to Mount Tensei, where Houou supposedly lives. So while he's not exactly a main character, he's the kind of guide who shows up at the right moment and knows way too much about one specific legendary Pokémon.
Content compiled by AnimeList.moe from publicly available sources.
