Lockport, anyone?
I could definitely see these “pea soupers” being a thing there, as the Leviathan blood refining process outputs noxious smoke that can sometimes settle over the streets.
Also love the mention of Linklighters, which were boys or men who would carry candles for people and guide them through the fog… but sometimes they’d lead you into an alley to be mugged. Seems very Blades!
The Lampblacks are sort of like linklighters if they grew up and got meaner 🙂
I’ve got plans to make a cityhack of Lockport, and I agree: this would be VERY cool for the setting.