DARKER THAN BLACK -黒の契約者- (Series) favorite_border

[DeepL Translation - needs review] Introduction to Volume 1: Ten years ago, an abnormal area called "Hell's Gate" suddenly appeared in Tokyo. Around the same time as its appearance, people with different abilities called "contractors" appeared. While searching for the person who holds the mystery of his missing sister, the contractor with extraordinary abilities, Hei Black, comes into contact with Kanade, a high school girl who is chasing after her father, who is supposed to be dead.

(Translator: DeepL)