Black Bullet Wiki
Black Bullet Wiki

For the race, see Gastrea.

Follow us on Twitter
Gastrea Virus
Gastrea Virus



Gasutorea Uirusu

Primary Ability




Image Gallery

Gastrea Virus (ガストレアウイルス Gasutorea Uirusu) is the virus that turns humans into Gastrea.


A mysterious virus that suddenly appeared before mankind in the year 2021. Because of its high contagiousness, it immediately spread throughout out the whole world. The humans and Gastrea went to war, with Gastrea arising on top. Presently, Gastrea stand above all else, claiming the spot at the top of the food chain and forcing humanity to barricade itself within Monoliths.[1]


Shape Corrosion

The Gastrea Virus' effect.

The virus enters the human body through bodily fluids, causing infections and altering the host's DNA and their form. Due to its high contagiousness, said virus spread throughout the entire world rather rapidly.[2] When a human being turns into a Gastrea, according to the size of the host, the hardness of its skin and the strength of its muscles will increase. Therefore, the bigger it is, the harder its skin and the stronger its muscles will become. The virus clones itself, and additionally analyzes the DNA of its host and adjusts its body shape accordingly.[3]

The erosion speed of the Gastrea Virus can be said to be very extraneous from every other living being on earth, and once the erosion exceeds fifty percent, the host can no longer maintain their human form; the host will turn into a Gastrea through Shape Corrosion. The Gastrea Virus has also been noted to grant the host with a new and unknown ability on top of their original power.[4] An exception to this are the Cursed Children, born around the time Gastrea first began. The Cursed Children are born with accumulated virus in their bodies, but are able to keep their human appearances.[5] However, they must take an Erosion Resistance Shot everyday in order to keep the erosion rate below fifty percent; otherwise, they will turn into a Gastrea.[6]


  1. Black Bullet Manga: Chapter 2, Page 1
  2. Black Bullet Manga: Chapter 1, Page 4
  3. Black Bullet Manga: Chapter 3, Pages 18-19
  4. Black Bullet Manga: Chapter 3, Pages 20-21
  5. Black Bullet Manga: Chapter 3, Pages 23-24
  6. Black Bullet Manga: Chapter 3, Page 27