Good day friends on Hive! Time to talk about 40k lore because even though I haven't played it in editions, I am still very much a walking library of Warhammer lore!
The thing to know about Space Marines is that they are genetically enhanced super-soldiers created by the Emperor to become the ultimate weapon to conquer and unify the human race as well as defeat and defend the enemies of mankind.
Originally, the Emperor made 20 Primarch sons, and from each son there was a Legion of Space Marines. After the Horus Heresy where half of the Space Marines went to Chaos (a whole other post), then the Legions were split up into 1000(max) man Chapters.
Some Chapters retained the homeworld of their Primarch while Successor Chapters spread out over the galaxy and took new homeworlds for their own.
At the time of the grimdark 40k, the administration of mankind and even the knowledge within a Chapter brings forth several situations. One issue is that the Administratum does not even have a reliable record of how MANY Space Marine Chapters there are!
It is generally accepted that there are roughly 1000 Space Marine Chapters in the galaxy.
The second issue is that sometimes even the Chapters themselves do not know where their own origins, obscured through the ages. Some then get the idea that they know their original Primarch but sometimes they are mistaken. This is also content for another time.
So now we consider that across the Imperium there are an unknown number of worlds, sometimes where the technological level of each is not equal! As long as they are a part of the Imperium and follow the Imperial Creed (The religion of the God-Emperor of Mankind) then they can have any culture or altered culture that you could imagine!
You can make up your own, but before you do that we must consider what is already out there!
Ultramarines of Macragge
An enlightened and integrated multi-planetary government, the Ultramarines have more than one vassal world. They have a decided Roman-esque feeling to them.
They embody nobility, bravery, and administration. As much as I make fun of them for being the Chapter of Space Marines who are the BEST at polishing armor, they are known to be formidable foes and now that their Primarch has awakened, few would be so foolish as to insult them.
Cato Sicarius again!
Because he has such an iconic Ultramarines look...
Source
Space Wolves
In contrast to the Ultramarines and their environment are the Space Wolves of Fenris. An Iced up Deathworld, Fenris is inhospitable and populated by warring tribesmen that are like Vikings. Fenrisians battle one another and all sorts of monsters that might fit better with a fantasy setting.
They have no concept of the Imperium or travel across the stars except for the vague notion in their myths that the Allfather(The Emperor) and Russ(Leman Russ, the Primarch of the Space Wolves chapter) make battle across the heavens.
The Choosers of the Slain arrive to pick up men who are slain in battle or just chose men that are still standing so they can become Space Wolves. This is considered a great honor and often tribes will ignore whatever battle they were having and merely fight to impress the Choosers.
The Young Wolf - Ragnar Blackmane
Youngest of the Wolf Lords on the Grand Annulus.
Source
As a character that takes up a similar position as Sicarius above Ragnar can be seen here together with his Fenrisian Wolves that go into battle with him. He is also armed with a variety of relics and bears honorific symbols and totems.
Ragnar is a warrior born and a berserker, using fury and tactics, he inspires his army to feats of great martial skill.
That's all for now! Thank you for reading!