Sigma/Synopsis

Sky Casino Arc
In the operation of Hunting Dogs in finding Lucy Maud Montgomery, Teruko leads a team towards the Sky Casino stating that Lucy and the others entered the casino, telling him there is a need to blockade the casino and deploy the police to every section. However, Sigma refuses to close the casino. After someone blew the exits of the casino, Sigma orders the soldiers to not panic and gives them personal orders.

While monitoring the events in the casino, he finds Michizō Tachihara in a hotel room where the RDG1800 counterfeit coins are kept in a safe. Panicking, he decides to make it explode in order to kill Tachihara, but he manages to stop the metal piece and prevent himself from the blast using his ability. After realizing he did not successfully kill him, Sigma decides to use his trump card, an aircraft to attack Tachihara. However, before reaching Tachihara, Teruko manages to stop it on time.

After Teruko's fight with the guards, Sigma orders the customers via their respective room's televisions to attack Teruko and Tachihara on sight and tells them that whoever manages to kill them will have their debts to the casino written off, promising to grant $10,000 to those who can knock them unconscious and $1,000,000 to those who can kill them. After managing to escape the customers, Teruko meets up with Sigma in the telecommunication room.

Sigma then faces Teruko and says that he can not and would not surrender and tells that even the key breaks it would be meaningless unless someone can override the controls with the key, they cannot block the detonation signal. Sigma then throws the key to Teruko. After giving it to her, Sigma attacks her with the Painless Gun, a weapon with a 7.62 mm ammo that can pierce even armored vehicles. However, Teruko manages to stop it and blocks its passage with knives.

Sigma then decides to add a new turret to the device, but Teruko stops him and hints that Sigma is done over. However, Sigma pulls out a directional resonance gun, pushes her onto the floor, and shoots her. After shooting her, Sigma shouts that those are the strength of his feelings. However, Teruko manages to stand up and push Sigma at the edge of the casino.

Teruko then offers Sigma two choices, surrender or else she'll drop him, Sigma again refuses and tells that he had no chance of winning and at that rate, both he and the casino will be destroyed. He then decides to drag Teruko along with him in order to save the casino. While falling, Sigma tightly holds onto Teruko's arms in order for her not to escape, but Teruko kicks him and manages to free from Sigma.

As Sigma is falling, Atsushi Nakajima grabs him and they manage to land at the box with the electric power installation at the casino's base level. Sigma asks Atsushi the reason for saving him. Atsushi replies that he saved him in order to save the Armed Detective Agency since he knows the location of the page. Sigma then asks Atsushi if he is sure he will tell him up front.

Ango Sakaguchi communicates with him through Atsushi's phone, telling him that he'd be able to read the memories of "the page". Sigma then states that he had taken measures against Ango's ability. Ango then replies that they just have to take it the old-fashioned way, torturing the subject until they speak since he cannot forgive the man who stabbed Taneda. Sigma then replies that he did not wish to stab the chief, it was only a threat and gives them the permission to ask him and states that after all, he did not understand what he was born for in the first place.

After the conversation, Nathaniel Hawthorne appears before them. Ango warns Atsushi to be careful with him since he intends to kill him and save Sigma, however, Nathaniel attacks Sigma causing him to fall. Sigma was saved by Atsushi. While grabbing on a pipe, Nathaniel shoots Atsushi on the forehead causing them to fall again, however, Atsushi barely saves himself and Sigma by using his tail as a rope. Sigma then orders Atsushi to let go of his hand or he will die too. Atsushi then shouts that he cannot let die someone whose last words is "I never understood what I was born for". Sigma then lets go of Atsushi's hand.

Sigma is seen falling and sees Nikolai Gogol waiting at the ground for him. After landing, Sigma wakes up at the sight of Gogol. Gogol then explains how he rescued him. Sigma then asks Gogol that if the one who gave instruction to shoot him was Fyodor, what is the reason for rescuing him and states that Gogol should have died during the hostage operation, Sigma asks Gogol how he survived and Gogol proceeds to tell him.

Sigma then states that the one he is surprised with is the fact the Gogol is expected to die yet he does not. Gogol then replies that Fyodor is the one who understood him but if they were to use Sigma's ability to read Fyodor's ability, they will be free from "brainwashing". Sigma asks Gogol why he chose him to do such thing, to which Gogol ultimately answers is for him to find his "home". Gogol tells him that he will never be able to find this home, unless he kills Fyodor. Moved with this dilemma, Sigma steels himself to end Fyodor's life to claim his home and ends up collaborating with Gogol to head out for their next act.

Vampire Infection Outbreak Arc
Sigma, together with Gogol, arrives at Meursault to which the latter uses his ability in order to free Fyodor and Osamu Dazai from their cells.

While Gogol, Fyodor, and Dazai talk about Gogol's proposed jail break duel, Sigma finds himself in an awkward setting. He sees Fyodor and Dazai inject themselves with the lethal poison given by Gogol. Afer Gogol's explanations of the facility's structure and security which will hinder the escape of the two, he is called by Gogol to present the "presents" he will give them for their aid on their escape. Sigma proceeds to show a table with four items presented on it. Shortly after, Fyodor chooses the keycard as his weapon as Sigma thinks Fyodor's plans are often unpredictable. During Dazai's turn to choose, he points to Sigma and chooses him as his weapon for escape. Sigma is then bewildered by Dazai's choice.

Sigma asks Dazai his motive for choosing him, but Dazai merely humors and even dances him around. Sigma eventually opts to go out by himself. He gets fed up with how Dazai does not seem to take the battle seriously, while he remains bent on finding his "home" away from those who manipulated him, including Fyodor, Gogol, and now Dazai.

The latter seemingly sees through him and promises to get him out of Meursault alive. They get interrupted by a commotion upstairs, which he deduces to be caused by another of Fyodor's pawns. As they arrive at the cause of the earlier commotion, Dazai concludes that Fyodor's next despicable card is the undead Chūya Nakahara, cementing Sigma's assumption that they cannot win against their two opponents.

Sigma continues to tag along Dazai while escaping Meursault, voicing that they are no match for the gravity manipulator. Dazai dismisses his concerns as they have an "angel" who can help them. Sigma deduces this to be someone from outside; Dazai confirms it to be Ango, with whom he exchanges messages. Sigma finds a fault in this setup: Dazai can only receive but not give messages. Eventually, they arrive at the central control room, where Sigma finds guards incapacitated all throughout. When asked how he did it, Dazai vaguely answers that he "stopped time".

Sigma once again grows suspicious of Dazai, knowing that his ability is ability nullification only. Dazai then reveals that a Meursault prisoner can stop time and, with Ango's intervention with the latter, stops time in Meursault as directed, which allowed Dazai to change the passcodes in the prison. Sigma soon muses how Fyodor had no chance against Dazai and his plan.