The Masked Assassin is the 46th chapter of the Bungou Stray Dogs Manga.
Fukuzawa is seen alone at night when he suddenly sees a trail of blood. He follows the trail, when suddenly it's a dead end. A masked assassin jumps behind Fukuzawa with a sword. Fukuzawa misses it just barley. The assassin chants death to ability users. Suddenly, from afar someone shoots Fukuzawa and he falls onto the ground. Back at the Agency, everyone is worried about Fukuzawa. Even Yosano cannot heal him. The Mafia are trying to hunt down the assassin. Mori and Elise are seen shopping, when suddenly a car explodes. The assassin is seen flying once more above the explosion. Dazai is also trying to find out who the assassin is. Immediately, he figues out who it is. At the explosion, Elise is seen flying and grabbing Mori by the neck. She lets him go and it turns out that Elise is Mori's ability. Mori then receives a call from Akutagawa. Akutagawa has found the assassin and goes after them. Akutagawa stabs the assassin and his masks is revealed. It turns out to be Nathaniel Hawthorne, but he has no idea who Akutagawa is anymore. Back with Mori, a police officer rushes over to the scene and asks what happened. Mori makes up some lie but the police officer comes over to Mori and stabs him. But Mori grabs the mask off the man and it turns out to be Fyodor. Elise comes flying at him but has lost sight of him. Fyodor is seen in an alleyway where he sheds his disguise and rummages through the bin to find where he put his hat. Fyodor turns around to see Dazai with his hat. Dazai then throws his hat on the ground. Dazai asks him what his intentions are as he has figured everything else out. Fyodor asks him if he means to say that they are alike. Fyodor then goes on to explain that the virus means mutual destruction. He explains that if they want to save Fukuzawa they would need to kill Mori. Fyodor then says that someone needs to get rid of these sins and that is why he is pursuing the Book. Suddenly, a sniper from behind shoots Dazai. Fyodor suddenly hears the voices of Kunikida and Atsushi calling for Dazai and exits the scene.