Cleansing the Tokyo Area

Cleansing the Tokyo Area is an event that takes place during the Civil Security arc.

Prologue
Detective Tadashima receives a call from an apparent building, the tenant claiming that the room above them kept leaking water. He heads to the scene and awaits for the Civil Security members sent to their aid. After a rather young-looking boy arrives, Tadashima's suspicion arises, questioning if he is truly the reinforcement; calling him a brat. Scratching the back of his head, the boy reassures him, and reminds him that if he does not wish to believe him, he will just head on back. Shocked at his remark, Tadashima asks for his license, which he receives and analyzes—Rentaro Satomi of Tendo Civil Security Corporation. Tadashima ponders the corporation's name, but is interrupted by Rentaro, who asks for an explanation to the mission. Briefly, Tadashima explains to Rentaro that shortly after receiving a call informing him of a "water leak," he and his men head out to the apartment building. Howbeit, he corrects his earlier statement and claims that the leak is in reality blood, not water. Stepping forward towards the building, he thanks Rentaro for coming and takes him to the incident's location; assuring him that Gastrea is involved.

As they walk to their destination, Tadashima converses with Rentaro and concurrently puzzles over his Initiator's whereabouts. Shaking, Rentaro informs him that he will not be needing her help for this mission, whilst at the same time recalling past events involving a conversation between him and his Initiator prior to her falling off their bike. Finally arriving to the room where blood is leaking, Tadashima is informed by his men that two other individuals have already entered the premises; angering him. However, Rentaro maintains his calm and steps up to the door, kicking it down whilst the detectives stand back. He looks around, but find nothing. As he sighs in relief, Rentaro is met by a voice from behind, leading him to turn around and witness a masked man standing in front of two crushed policemen. The two quickly engage in a fight when the man admits that he is the one who killed them. Overpowered, Rentaro can only watch as the man jumps out of the window after shooting two policemen and receiving a call on his phone. Tadashima enters the room, shaking Rentaro and reminding him of their real objective.

Cleansing
Snapping out of his shock after engaging the masked man, Rentaro turns his head around and shouts at the detectives to begin searching for the source of the infection. However, they are unable to locate the source, but eventually stumble upon a puddle of blood after Rentaro questions Sumiaki Okajima's, the man leaving in the apartment, status. Tadashima informs him that the man was divorced and lived alone. Examining their surroundings, Rentaro concludes that Sumiaki was attacked by the Gastrea and jumped out of the window to look for help. Albeit, he also takes into consideration the amount of blood on the floor, speculating that Sumiaki is now infected with the Gastrea Virus. Tadashima stares at him in shocked, realizing that they now have to deal with the source of the infection and the infected. Turning to face Tadashima, Rentaro reminds him that if the infection spreads, trouble will surely arise for him.

Enju walks about complaining about Rentaro leaving her, his fiancé, behind. When suddenly, a man comes behind her, asking for directions. Initially, she informs him that he will soon leave this world, which shocks the man. Revealing his name to be Tadashima, he understands what the young girl means to convey after looking at his destroyed body; remember the Gastrea that attacked him prior to arriving where he currently is. Before he begins to process of Shape Corrosion, he tells Enju to apologize to his family. Just then, he transforms into a Gastrea, which leads Enju to initiate her Initiator's abilities and fight the man. However, she is cough off guard when Sumiaki releases a Sticky Web that bounds her to the ground.

Running outside in search of the Gastrea, Tadashima receives calls from all of the teams assigned to several locations, all confirming that the Gastrea in nowhere to be found. Furious, he slams his fist on a pole while complaining about the lack of information. Just then, he looks at Rentaro and questions his actions, only to be shown a trail of blood on the floor. Before they can continue to converse, a loud roar is heard, leading them to run towards it in hopes of locating the infected. They arrive, and are met by a Stage I Spider Type Gastrea. Rentaro reaches for his Springfield XD, but Tadashima is quick to shoot at with his gun; proving futile. Turning around, Rentaro jumps and takes Tadashima with him to prevent the jumping Gastrea from attacking him as well. Quickly after lecturing him, Rentaro takes his XD once again and shoots the Gastrea, causing damage. However, moving closer to the Gastrea, Rentaro is shocked when it turns out to be alive. Albeit, before it can attack him, a young girl comes in an kicks the Gastrea to its death. Standing in front of Rentaro, Enju states her name and informs Tadashima that she is Rentaro's Initiator.

Aftermath
With the blood-clad Gastrea lying on the floor, Tadashima takes a closer look at it and finds it impossible to believe that those infected by the virus turn into noted monsters. Interrupted by Rentaro, Tadashima turns to face him, only to be met by the young boy lowering his head and apologizing for being careless with a low level enemy. Tadashima informs him that it is okay, but inquires about Rentaro's bullets that were able to harm the Gastrea. Rentaro takes out one of his bullets and explains that Varanium was used to create them, naming them Black Bullets. He then faces Enju, questioning the sudden change in her eye color; only to be told that it's the results of her Initiator abilities. After Enju heals an injury on her back caused by the Gastrea, Rentaro and Enju part ways with the man, informing him that they must arrive to a special sell before it ends.

As Rentaro and Enju run towards the sell, Tadashima speaks to one of his men and ponders about the Gastrea and Cursed Children. Meanwhile, Rentaro speaks to Enju about the Monoliths protecting them by keeping the Gastrea away. Tadashima looks out towards the Monoliths, recalling Rentaro's words. Shortly thereafter, Rentaro returns to Tendo Civil Security and is met by an angry president that yaps at him for forgetting the reward money. After lecturing him, Kisara returns to her seat and informs Rentaro that the source of the infection has not been located, leaving him in shock.