Vale believed that the Dark Arts Faction of the past lacks something very important which is why they've lost against a small number of experts even with the advantage of having a fortified camp.
It is their failure to take advantage of the technological advancement of mankind.
Although spells, rituals, mystical items, and other arcane techniques are incredibly powerful and useful in battles, they should've taken advantage of the technological advancement that mankind has developed…
Guns and explosives.
Vale started writing about how powerful the guns and explosives can be… He noted how they were used by the police or the military to protect the peace and security of not just a city but the whole kingdom itself.
Anyway, based on the books he read, a revolver can still shoot to death the Third-Class and Second-Class Arcane Arts Practitioners.