It’s not a new thought, but I really like how Tokyo Ghoul ends up forming a general Ghoul culture as the narrative starts to expand and that it makes sense to think about. It just kind of gives them a particular flavor that makes them feel humanized, but still excluded from the Washuu-enforced society. It’s very shaped by how ghouls are constantly on the back foot, that the CCG (and other organizations) will hunt you down and kill you simply for being a ghoul, and that this isn’t a new experience. It’s shaped how they do things as a group.
Masks are the main thing I tend to think about. They’re an obvious narrative solution to Kaneki’s problem of suddenly being a Ghoul—and the central issue all Ghouls have to contend with. Their existence is based around eating people, which is why they’re hunted in the first place. It doesn’t matter if a Ghoul likes humans or hates them, in order to survive they have to kill others.
Admittedly, it didn’t really click in my brain that it was a general “Ghoul-thing” until the Qunix went undercover as ghouls, and so they were outfitted with masks. From then on, I noticed that masks weren’t really exclusively a hunting thing. Ghouls wore them when they were just out at night or hanging around in public, identifiably as ghouls. The CCG’s codenames come from kagunes sometimes, but more frequently they’re based on masks (it makes me wonder if masks are a way of taking back control of identity in a way)
It just made me realize that masks weren’t just a solution narratively, but they’re an extension and symbol of ghouls and their relationship with a hostile society. It’s not just a localized thing for the Anteiku ghouls or a gimmick, nearly every ghoul has a mask. Even developing a kakuja comes with a biological mask
There are other things too, notably the Ghoul Wedding stuff (ceremony, outfits, traditions) and the stories of the One-Eyed King that's based around the ancient king.
I'm not sure I can dive into it the way I want to currently, but I just think it's a neat part of the story and it's not hard to think of how different things fit into it. Like, it's easy to imagine how Kakuja would probably feature as "boogeymen" in stories for kids, as a cautionary story against cannibalism
