Nanatsu no Taizai: Edinburgh no Kyuuketsuki

Twelve years ago, a messenger of a neighboring country of Lioness—Edinburgh—announced that there were vampires. The inhabitants of Edinburgh were either killed or transformed into vampires, and so the capital was taken from them. The captain of the holy knights Zaratras, Dreyfus, Hendricksen, and Meliodas made a conference between the leaders, where it was decided to form the group of riders: "Seven Deadly Sins", who are tasked to recapture Edinburgh.