Civil Security arc

The Civil Security arc is the first story arc of the Black Bullet series.

Ten years after the Gastrea parasites begin to claw their way onto the top of the food chain, humanity's hope lies at the hands of Civil Security, an organization specialized in fighting Gastrea. Promoter Rentaro Satomi and his Initiator Enju Aihara are tasked by Kisara Tendō to investigate an area in Tokyo said to be breached by a Gastrea.

Enter: Civil Security
In the year 2021 mankind faces the alien creatures known as Gastrea, a mysterious virus that took humanity by surprise; entering the human body through body fluids, altering the victim's DNA and body structure sequentially. Ten years later, Gastrea has easily taken mankind's spot at the top of the food chain. Presently, a policeman talks to a young kid claiming to be from Civil Security, his age leading the man to believe that he is lying. Scratching his head, the young boy persists, claiming to be the reinforcement sent by Civil Security; informing the man that if he will not trust him, he shall head back immediately. The man solely notes the young boy's persona, and takes a look at his uniform as he determines he is a student. He then asks the young boy, named Rentaro Satomi, to show him his badge as several kids nowadays are pretending to be of Civil Security. When Rentaro gives him his badge, the man looks at it and claims to of never heard of the title of his company before. The two greet one another properly and rapidly get down to business. Tadashima can only sigh as he walks towards the building where the "accident" took place and reveals to Rentaro that reports show that people kept contacting the police about a strange water leak on the top floor, but instead of water, states Tadashima, it was blood. As he walks towards the building, he thanks Rentaro for finally arriving, as it is thanks to him that they can finally investigate further. As Rentaro thinks to himself about Civil Security and its purpose, being to fight against Gastrea, Tadashima brings him out of his thoughts when he questions his Initiator's whereabouts.