Twist: the White-Haired God-Slayer

In Britannia in the 19th century, the people lived an extremely difficult life under the weight of the cross. The resentment caused by many people eventually caused the collapse of the Devil's Gate. A large number of demons poured into the world. They devoured souls and transformed the terrain of the world. The remaining army collapsed in an instant. In order to survive, the original Britannia government united the state religions to form the country's highest governing body "β", establishing Wulip, Manchester, Belfast, and Coventry. There are 4 β branches, London is the β headquarters, and demon hunter guilds directly affiliated with β have been set up in various places. Faced with the crisis of the world turning into hell, how can humans resist?