AR∀GO: London Shikei Tokushu Hanzai Sousakan

AR∀GO ―ロンドン市警特殊犯罪捜査官―

The story centers around two twins, Arago and Yuan, whose parents were slaughtered by monsters. Years later, the vengeful Arago crosses paths with Yuan, who has since become a police officer, just as blood begins to flow again in the streets of London. (Source: ANN)