Trailer:

0:05-0:12
Fyodor: The spread of this mist is already unstoppable. The earth will become the fruit of death—it will become a dead apple.

0:22-0:25
Atsushi: At all times, the boy is always standing with the tiger, in order to live!

0:25-0:28
Dazai: Did you think you would be able to capture me? 

0:29-0:32
Kyouka: I just want that person to be in the world of light. 

0:32-0:34
Akutagawa: Dazai-san…will be killed by me.

0:35-0:40
Shibusawa (?): –because all the Abilities in Yokohama will soon become mine. 

0:40-0:44
Dazai (?): If I touch this and make it disappear, everything will end.

Synopsis on BSD Site:

It began—six years ago.
The 88-days “Dragon’s Head Dispute”, which drew in each and every organization into a violent storm of blood, went down in the history of Yokohama’s underbelly as the dispute with the largest number of fatalities.
Dazai Osamu, who had escaped death together with his Port Mafia ally, Nakahara Chuuya, clung onto the words of his dead friend and bid farewell to his boss, Mori Ougai, and he was only seen in his new place two years afterwards. 

The Armed Detective Agency, formed on the foundation of Fukuzawa’s ideals, welcomed Nakajima Atsushi and Izumi Kyouka as their new members, and they are living boisterous yet peaceful days.
However, strange incidents of Ability users around the world successively committing suicide are happening now.
Incredibly, more than 500 Ability users have used their own Abilities to kill themselves.
And at every site, an inexplicable “mist” had been found.
The Special Abilities Department in the Ministry of Home Affairs have called this case “Serial Suicides of Special Ability Users”.
The Armed Detective Agency, having received a request from Sakaguchi Ango, have set out to capture the man suspected of involvement in this case.
His name is–Shibusawa Tatsuhiko.
Called “The Collector”, he is an Ability user wrapped in mystery.
He’s hidden in Yokohama with his own motives, but there too, the demon Fyodor, secretly involved in various cases, has been appearing and disappearing at will…working to engulf Yokohama in a nightmare.

Unprecedented strong opponents, attacking the Ability users one after another.
And while this is happening, Dazai disappears.
Atsushi, who had received strict orders under Kunikida Doppo’s command, to “eliminate the mastermind”, runs to the enemy’s fortress with Kyouka.
Yet Akutagwa Ryuunosuke, from Port Mafia, stands in his way.
What is the truth that his sworn enemy Akutagawa tells him, a truth Atsushi hadn’t even imagined?
And at the same time, carrying the regret of having lost his comrades in the past, Chuuya faces his foe…… 

Shibusawa, who has appeared as though to put an end to a tedious world.
Fyodor, moving in the darkness.
And Dazai, who has disappeared into the mist.
In a mist from which nothing beyond can be seen, bound by the red strings of fate that have twined around each other from distant days, the story is headed—