There was the terrified bystander Bones interrogated who gave us some info on the workings of the city.
*c*< Though for that matter, I'm surprised Scrooge's giant moneybin isn't included in the scenery of Nexus City.
Using Tywin's claims to "divine justice" as an excuse is just bullshit, though. Just because he claims some arbitrary "divinity" that doesn't mean he has any more right to judge the actions of others than anyone else does. Murdering people in cold blood is not any more justified just because some god or some government gave you permission.
That comment wasn't meant to be entirely serious.
True that cold blooded murder is never alright just because someone gave you permission, but life is a chaotic cesspool of viewpoints and beliefs mashing, colliding and trampling against each other, with everyone just trying to do things in a way that they believe is right, or if they aren't able to
do right because of some unfairness out there, at least do the best they can. From Tywin's viewpoint, I'm guessing that dispensing what he sees as fair justice isn't just an enforcing of his beliefs, it's likely part of his very identity, and something he can so strongly trust in because he can say it is his birthright by divine power.