This article covers the in universe; The Order
The Order is an organization dedicated to protecting the Human Realm. Entrusted with the world by the Angels of the Afterlife themselves, The Order has been raging War against the Demons since Sparda's death.
The Order is an organization inspired by Dark Knight Sparda himself. They guided by the Angels of the Afterlife in order to protect Humanity from Demon Temptation and Demonic Tyranny. The Order has counteracted the efforts of Demon Temptation with "The Cross"; a building in each region controlled by the order which has a direct link to the Angelic World where the Angels can counteract the Sins Temptation.
The Order works to militarize itself by using volunteer humans in order to take territories back from the Demons. They train Humans in their own select class and order them under their command. The overall goal of the Military is to spread the Cross in order one day rid the world of temptation forever. Although the Order lacks physical arms when compared to the Demons; Seven Hells, they have an advantage in number, organization, intelligence and devotion.