So I was going through books and telling one of my new players last weekend how people (ie humans) mostly in 40k appear either looking like Military Personnel (sort of like 18th century military uniforms or or WW1 / WW2) or Mad Max types (albeit "space" post apocalyptic types)...

I got my reckoning based on all the art I've seen but mostly from Old White Dwarf mags

I went as so far as to tell my player Google Necromunda to get an idea what the "humans" look like these days LOL

What would you tell a player about how "normal" or "set-dressing" (background) human's dress and act?

On top of that - is there any good writie ups on a Hive besides Necromunda and or Desoleum?

I wanted to get a good idea how "bad" (aka Aggro) such places are...

Personally in RL I came from a background where in the street - you looked at someone too long or wrong and there was a chance an encounter could happen involving a gun > roll initiative (my character runs lol) - of that some players think I might be a "bully" by doing such random encounters (....why are they attacking... thats stupid - comes to mind).

The bottom end of criminality and where they hold themselves doesn't take much for trouble to rear its ugly head has been my experience (makes me wonder if Martin Scorsese came from "the hood" too - I know Robert E. Howard got to grow up in boom-town and got exposed to life's rough side because of it > which flavored his writing and the content therein)

Anyways

A. What do people look like - and how do they act?

B. Hive City Life / Culture?

C. How Aggro is the populace of humans in regards to senseless (random encounter) violence?

Your aggro bot

Morbid

-Humans are as ever human. Most have faith in something and follow those rules. They dress for their surrounding if they can or their livelihood if they can afford it. It's not like T Shirts and Jeans are gone or anything, people just don't feel the need to wear them. Go to an aggro world and you're likely to find simple garb in pants and short sleeve shirts as long as the atmosphere is safe enough.

-Scintillia is a hive if I remember right there's some stuff in first edition about it. Same wifh Fenksworld. The problem is there isn't a huge writeup on them like Desoleum or Necromunda it's scattered in bits and pieces.

-Aggro: same as any place really. There are places you don't go and you'll be fine staying out of there. Gang activity is a fact of life. That's why we have PDF troopers and Arbites for the really dangerous times.

In my interpretation of Hive Cities, the majority of the population would tend to wear regimented clothing such as that seen in most dystopian novels, 1984 being the prime example. I could imagine a society that would be quite morose on some of the more harsh worlds, especially among the "middle" aka working class. The drudgery of everyday life would also give rise to a lot of propaganda and government sponsored entertainment, again taking 1984 as an example. You could see public executions or movies glorifying the Imperial Guard or the lives of great heroes or Saints alongside more mundane institutions such as bars and brothels which would of course be tolerated if not promoted by the ruling class. Among the dredges of society, it would be much more varied and more akin to what you're describing from the Necromunda books. There your choice of clothing would reflect allegiance to a certain gang or cult, supported by an individual's behavior, body modification such as tatoos or even where they live. As to violence, in all levels of society I would see it as accepted if not applauded. Arbites are often described as brutal in their enforcing of the law, which itself is quite harsh and often deadly with its punishments. Towards enemies of the state, xenos, heretics or otherwise, the application of violence would be lauded. I can imagine hate videos to rouse crowds against mutants or an alien menace on worlds plagued by them. Especially in the underhives violence would probably be a common fact of life, and even the middle class would be ruled over through fear of Enforcers and the Arbites.

Here are some minis I made to represent civilians in the 40Kverse:

the way I see hive society

the nobles are extremely decadent fancy impractical outfits exotic imported off world food surrounded by bodyguards lackeys and people who can do neat tricks to impress the other nobles and their lackeys duels of honor and assassination and general intrigue common.

army: most likely experienced in antiriot and urban warfare (due to training and actual combat) main incentive to join besides jingoism is general better living conditions compared to alternatives even if army is a unified whole the nobility will most likely to have own standing forces/ militias command will have varying levels of competence due to nepotism and cronyism.

police: brutal no sensitivity training understaffed overworked and most likely corrupt if you want a crime to be solved you better be rich or a noble otherwise screw you most likely equipped like modern swat forces trained to stop riots and keep everybody working.

working man: working in sweatshop conditions and in many cases the factory has a priest to give sermons about how they're working their sin away for the afterlife while they are working manylive in giant company towns owned by the nobles or merchants many hives have the bread and circuses root of rome minus the bread and have free carnivals blood sports and other things to keep the populous happy others don't make them free but still have them food mostly consists of corpse rations or other nutritious but bland food with various canned and other preserved food added but due to the population size food shortages and the soon to follow food riots are a ever present danger slavery is also usually legal in some form weither wage slavey indentured servitude or chattel.chattel slaves are commonly given cheap bionics in the form of buzzsaws scissor blades or jackhammers either to aid them in their work or equipping them as gladiators with weapons you literally have to disarm to disarm.

crime criminals of all shapes and sizes gangs prevalent especialy in the lower/underhive various drugs made from various funguses and moss and chemicals Obscura(meth) being one of the most common weapons and stolen factory goods and food are common blackmarket items they're are also cutter gangs( think organ harvesting but for bionics) and protection rackets are fairly common( and in some cases give better job at protecting then the police)

underhive: filled with small towns/cities mostly controlled by gangs or people who hire the gangs surrounded by urban wilderness mutations are common so is death food water and power are scarce with many villages build around a old water pipe or broken wire that has yet to be shut off food mostly consists of various rodents and other scavenging animals fungus and if all else fails human flesh.

The Eisenhorn , Ravenor and Calpurnia series are all fairly good for showing a wide variety of civilian societies. It's also not a bad idea to take inspiration from GW's cribbing from real history. For example, the Drookian Fentroopers are basically Anglo-Scots Borderers, and it's quite obvious whoever fluffed them out had read GM Fraser's history The Steel Bonnets . Basically imagine a decentralized medieval society in a hilly, swampy area, riven with warring, feuding families (I suspect Game of Thrones cribs a lot from them too - the Neck in particular fits) and trained as expert light cavalry - Brettonian squires would be perfect minis for a Drookian army. Fraser's novel Candlemass Road set in the same place and period is incredibly dark and atmospheric and could easily inspire an investigation set set on Drook, or any other medieval world.

Basically, pick your favorite novel, read it thoroughly, and steal. There are any number of noir detective novels and Humphrey Bogart films, for example, which could inspire a hive (they also inspire life in Star Wars' Coruscant in the novels.