Photo Source: Cosplay Costumes of Halibel Cosplay from CosplayFU.com
Ten years ago, an inscrutable and abnormal territory known as Hell's Gate appeared in Tokyo, altering the sky and wreaking havoc on the landscape. The heavenly bodies disappeared, replaced by false stars. During this time, people who possess various special abilities emerged. Kept secret from the masses, these individuals, known as Contractors, are able to murder in cold blood.