The @Vanguard are humans infused with demon blood in order to hunt demons and other undead creatures. Because they have demon blood in them and a bad reputation thanks to the ones who've lost themselves to their demon power, they're all under oath not to harm humans no matter what.
And due to how volatile men can be with the power, they only allow women to become vanguard.
They operate in @The Fortress to arm and train their members. It’s also where they take contacts and delegate them out.