Based on the visual novel of the same name.
The Official website of the Dies irae Visual Novel has revealed that the anime adaptation will come in the Fall 2017 Season and the director will be Susumu Kudo (Ghost in the Shell Arise 4) menawhile Takashi Masada (Dies Irae Visual Novel) will be writting the adaptation.
Anime News Network describes the history as follows:
“The game and anime’s story features an alternate history of World War II. On May 1, 1945 in Berlin, as the Red Army raises the Soviet flag over the Reichskanzlei, a group of Nazi officers conduct a ritual. For them, the slaughter in the city is nothing but the perfect ritual sacrifice in order to bring back the Order of the 13 Lances, a group of supermen whose coming would bring the world’s destruction. Years later, no one knows if this group of officers succeeded, or whether they lived or died. Few know of their existence, and even those who knew began to pass away as the decades passed.
Now in December in the present day in Suwahara City, Ren Fujii spends his days at the hospital. It has been 2 months since the incident that brought him to the hospital: a fight with his friend Shirou Yusa where they almost tried to kill each other. He tries to value what he has left to him, but every night he sees the same dream: A guillotine. Murderers who hunt people, and the black clothed knights who pursue the murderers. He is desperate to return to his normal, everyday life, but even now he hears Shirou’s words: “Everyone who remains in this city eventually loses their minds.”
Via: Anime News Network