Vampire Infection Outbreak Arc

Vampire Infection Outbreak Arc (吸血鬼感染の発生編,) is the ninth story arc in Bungo Stray Dogs and is the sixth story arc in the Decay of the Angel Saga. It focuses on the fifth and final member of the Decay of the Angel and their ability causing a worldwide contagion.

Synopsis
After the battle with Kamui, the next stage for the Decay of the Angel plan commences - turning people into vampires and eventually controlling the humankind. The United Nations decides to release One Order, an ability weapon that can help suppress the vampire infection. Knowing Kamui's identity, the Armed Detective Agency also plans their move to retrieve the weapon.

Fight against Fukuchi Aftermath
After Akutagawa and Atsushi loose to Fukuchi, Atsushi manages to escape from the scene using a submersible and is rescued by Ango shortly after. After the battle, several guards came rushing to the area as Fukuchi ordered them to track the terrorist who escaped in a submersible.

Bram Stoker's Appearance
After the guards leave the scene, Fukuchi brings out a coffin and lets out the last and fifth member of the Decay of the Angel, Bram Stoker. With Fukuchi's threat to sear the Holy Sword attached to Bram into his brain, Bram obeys Fukuchi and bites into Akutagawa, eventually turning him into a vampire.

After Akutagawa turns into a vampire, a vampire outbreak begins to spread, turning some mafiosi to vampires. As a witness of the said event, Tachihara reports to his fellow Hunting Dogs members, giving them the idea that the Armed Detective Agency is behind it. On the other hand, Tachihara stands his ground, telling them to re-evaluate their investigation on the Agency as the true culprits as he believes there truly is a real mastermind behind the course of events recently happening.

Trivia

 * This is the longest arc in the manga to date, being published for 3 years as of now and the number of chapters so far being 35 with The Guild Arc coming in at second.