The guards take his coin, seeing, but apparently not recognizing the assassin's mark; at the very least, they give no reaction to it. Once he's passed over the money, though, they nod and unlock the gate for him, letting him into the small village that's been constructed, to serve the fortress. A general store, a flophouse, a tavern and a brothel round out the services, along with a few small shacks for the citizens to live in.