Fukuzawa realizes that Ranpo’s "gift" will eventually get him killed or ostracized because of his lack of social filter and the resentment he draws from others. To give Ranpo a way to navigate the world, Fukuzawa lies to him:
The first episode of Bungou Stray Dogs Season 4, titled serves as the beginning of the "The Untold Origins of the Detective Agency" arc. It is a flashback episode set approximately 12 years before the main series, focusing on how Yukichi Fukuzawa and Ranpo Edogawa first met . A Chance Encounter Bungou Stray Dogs 4 Episodio 1
Ranpo quickly proves his genius by solving the murder case Fukuzawa was investigating in a matter of seconds. He identifies the killer not through supernatural powers, but through pure, terrifyingly sharp observation. However, Ranpo is distressed; he doesn't realize he is a genius. He believes the world is "scary" because everyone else seems to be playing a game he doesn't understand, or deliberately acting stupid. The Birth of a Partnership Fukuzawa realizes that Ranpo’s "gift" will eventually get