Atsushi Nakajima vs. Mark Twain

Atsushi Nakajima vs. Mark Twain is a battle between Armed Detective Agency member Atsushi Nakajima against Guild member Mark Twain.

It happened when Atsushi escaped the Moby Dick with the goal to deliver Q's doll to Osamu Dazai in order to nullify it.

Prologue
After being captured by the Guild and being locked up in a room at the Moby Dick, Atsushi encounters Lucy Maud Montgomery outside the room who is on her way to burn Q's doll. Afer some convincing, Atsushi manages to sway Lucy's thoughts and symphatize with her, resulting to Lucy helping him escape from the Moby Dick. After being informed about Atsushi's escape, Fitzgerald immediately orders to activate the anti-air cannon.

Battle
During Atsushi's escape, Twain immediately goes to the controls. With his ability activated, he immediately finds Atsushi's targets and is able to destroy Atsushi's parachute. As a result, Atsushi has been knocked out however he manages to land safely to the ground thanks to his ability.

Shortly after Atsushi's landing, Twain aims at Atsushi and shoots at him continuously. While trying to avoid Twain's attacks, he finds the city with casualties due to the activation of Q's curse. In the middle of this, he spots a baby in a crib crying and passes it to Michizō Tachihara telling to take care of the baby.

Twain becomes amazed by Atsushi surviving the huge fall and his gunfire together with not taking his .50-cal attacks without a scratch. Twain then declares the hunt as his mano-a-mano duel with Atsushi. He immediately spots a fuel tanker near Atsushi and blows it. As a result, Atsushi's legs have become shattered. As Atsushi tries to grab the doll after the explosion, Dazai appears before him telling Atsushi that he won. Atsushi tries to warn him as he is being fired from above. However, Dazai activates the smoke screen he installed before causing the anti-air cannon's heat sensors and radars to be down. Unable to locate the two, Twain just laughts in defeat.

Aftermath
Dazai immediately nullifies the doll ending the curse in the city. After getting into a safe place, Atsushi asks Dazai how did he know his location to which Dazai responds that he has been watching Atsushi's direction of fall. Dazai soon talks about Q being held by the Guild and the possibility that the Guild can stage the chaos any time in addition with the Special Division for Unusual Powers being in a state of uncertainty. Atsushi then suggest to Dazai that the Agency couldn't have a better ally than the Port Mafia.

Manga and Anime Differences

 * In the manga, Atsushi doesn't originally have the partial transformation activated (including tiger's hands)However, he is on his partial transformation form in the anime.
 * While shooting Atsushi, Tom originally talks to Twain about him missing his target.
 * In the manga, Atsushi originally encounters Michizō Tachihara during the chaos.
 * In the anime, after the fuel tanker explosion, Atsushi had a brief memory of the orphanage director.
 * Dazai originally nullifies the doll after activating the smoke screen In the anime, Dazai nullifies it as soon as he meets Atsushi.