Thank you- perhaps I shall.
to give you brief it's a sci fi space opera with some fantasy elements. The whole point of it is to be had dark has it can while keeping some semblance of sense. The whole point is there exist no good guys only shades of black and grey.
The first and most important faction is the imperium of man. A fascist state that controls 2/3 of the galaxy. Founded by a highly psychic l individual known only the Emperor. Who tried to reunite mankind after the collapse of the previous government. So in order to conquer the billons of plants and moons humanity has settled he make 24 generically engineered supermen called primarchs vulkan is one of them they command legions of generically and cybernetically modified super soldiers called space marines . To make a long story short half the primarchs and there space marines fall to chaos a civil war happens and the emperor gets put life support holding back a rift that threatens to give literal demons a foothold on Earth. And in the past 10k years his empire has started to worship him has a god even though he tried to wipe out religion. and the empire has regressed in terms of technology is now a fascist theocracy hellbent and killing every alien and human who doesn't worship the emperor in the galaxy.
Chaos is the main villain's they are made up of four gods who are in a constant struggle for domaince over each other and the galaxy. they feed have the emotions of humans and sentient aliens. The gods inhabit another plane of existence called the warp. FTl works in this universe by taking shortcuts through the warp. They also corrupt mortals to fight with them like the 12 rebel primarchs and there space marines
Tzeentch the god of psychic powers change and intrigue. He is constantly scheming and has influence in pretty much every thing that goes on in the galaxy . Nurge a god of disease who is constantly cooking up plagues to unleash upon the galaxy.
Khorne the god of war and violence in general.
And slannesh a god of hedonism. Her birth by the way was the cause of the pre empire humanity's collapse. It made ftl impossible
Orks are bioweapons made by a extinct race called the old ones. They are fantasy Orcs but in space with a few twists they preproduce by spores so when they get on a planet you have a infestation of them now. And they instinctively understand how to build weapons' and other technology and they also have a strong desire for war. They are not unified and they exist has a myraid of small pirate fleets to small empire that managed to hold a couple of solar systems. From to time a waagh forms where one orc warlord unifies a few other groups into a large hoard.
The Eldar are space elves their degeneracy created slannesh and gave the warp a foot hold into the galaxy by creating the eye of terror that consumed the center of the galaxy.
Now we have two factions of Eldar.
Plain elders they basically become a very harsh stoic society were they try to suppress there emotions and desires in hopes and avoiding being consumed by slannesh.
The Dark Eldar said fuck it and tripled down on there degeneracy their society revolves around the capture of slaves which the inflict sadomastic torture on. There society also runs like a parody of Anarcho-capitalism.
The tau are confederacy of many different alien around elven last time I checked. The main species of the empire are the tau they have a weak form of eusociality made up of castes with morphological differences but all castes are fertile and only breed with each other. Being a member of the Tau empire has its advantages they have the best quality of life of any main faction many human worlds on the edges of the Imperium for this reason. They have also fought the Imperium to a standstill with their tech advantages. Its not all good though. The life of a person under Tau rule is micro managed by the ethereals the tau ruling caste. They decide who you can marry how many kids you can have pretty much everything with reeducation camps for those who disagree. Tau strictly enforce the Caste system in the books member a member of the water caste who take up the roles of merchants diplomates and administrators was lobotomized for taking up sculpture has a hobby has its not seen has okay for water caste to do that.
Note that the caste sytem does not apply to other races under tau rule.
Also there two other main factions but this post is getting long so am going to stop. Also in lore its stated thousand of alien race exist in the galaxy but only a handful have been named. There lore for the most parts boils down to there name and that they have been wiped outed by humans or they are currently among the edges of human space causing problems. Or that they are under Tau rule.
Basically the lore exist has serious of novels and rules books for the table top game.
