This is probably the nerdiest post I will ever make, and one that has been a long time in the making. At the end of July 2023 I decided to start studying the lore of one of my favourite video game franchises; The Elder Scrolls. It has one of the most expansive, complicated and detailed worlds ever, and it relies heavily on the "unreliable narrator" meaning that every event has at least two perspectives and both are true even when contradicting each other, because both characters are retelling what happened from their individual perspectives. Each account is their truth, even if it might not be the overarching truth or the whole truth.
Unless you go around reading every single book you find, the general gameplay experience will offer you a very limited view on lore. It's when you start drawing connections between events described in books and described by NPCs and even from Out of Game texts that you start to glimpse how fucking huge this universe is and how much attention to detail has gone into it. And once you start studying the lore you simultaneously find yourself studying philosophy, psychology and comparative religion.
So how do I even start trying to make the lore make sense for the uninitiated? Let's start with Skyrim, the most recent main game in the franchise.
The first thing that happens after the initial cutscene is that you get to create your character. You have ten choices for race. Altmer, Argonian, Bosmer, Breton, Dunmer, Imperial, Khajiit, Nord, Orc, and Redguard.
The Altmer, or High Elves, are a race of elves who view themselves as closest to the original race of elves which all other elvish races sprung from: the Aldmer. Their culture is obsessed with preserving this purity and because of this purity they view themselves as superior to all others. According to legend the Aldmer were descended from the gods and the Altmer view it as their biological right to attempt to re-ascend to godhood. Some of their cultural heroes, like Phynaster and Syrabane, have allegedly done this. Their most revered god is Auriel, the God of Time. They hail from the island province of Summerset.
The Argonians are the lizard people, who are on the outside of the man/elf schism. They hail from the swamps of the southeast, Black Marsh, and they live in a tribal society where they worship the Hist, a sentient race of trees. Every tribe has their own Hist tree and the Argonians consume its sap on their name day to receive their name and connection to their Hist. It's said that the Hist saw the other mortal races and found that those forms were useful so the Hist created its own version of that form: the Argonians. The Hist can influence the Argonians and even change their form or gender. Aside from the Hist they also worship Sithis, the primordial cosmic force of change. They experience life from the aurbic now, meaning the past isn't important and the future is unknown so they live in the present. Argonians see change as good and accepts that nothing ever lasts.
The Bosmer, or Wood Elves, are a race of elves who live in the deep forests of migrating trees in the southwest, Valenwood. They worship Y'ffre and view existence as a story told by him. To honour him they follow the Green Pact, which says that the forest can't be harmed. So they can't chop down trees or farm or pick vegetables. They eat meat. Even the meat of fallen people as it's against the Green Pact to allow the dead to sink into the ground. Their weapons and armour are made of bone and carapace and sinew. The Green Pact states that if they care for the forest, the forest will provide for them and this gives them the ability to shape the trees to their liking, into dwellings. Unlike the Altmer, they don't view themselves as superior and like the Argonians they also prefer to live in the aurbic now. The Wild Hunt is a ritual the Bosmer can perform in times of great danger which allows them to transform into eldritch monsters that will devour everything in their path. Once transformed, they can't turn back.
Bretons are a mix of man and mer. In ancient times a House of Altmer, the Direnni, arrived on the shores to the northwest, High Rock, and settled there. They eventually encountered human tribes which they took as their concubines. The eventual offspring would result in the Bretons, a race that looks like men but with the magical affinity of elves. Eventually the Bretons revolted against the Direnni and took the region for their own. The region consists of very many small kingdoms and dukedoms and they have a culture centered around knighthood and questing. They follow the Imperial pantheon with Akatosh, the God of Time, as their main deity.
Dunmer, or Dark Elves, are a race of elves of live in the volcanic ashlands to the east, Morrowind. Originally called Chimer they broke off from the Aldmer in ancient times and travelled across the continent to their new homeland. The reason they broke off was due to religious differences from the Aldmer, the Chimer instead chose to venerate the Three Good Daedra: Azura, Mephala and Boethiah. Quite some time later these three gods would be exchanged for the living gods of the Tribunal: Almalexia, Sotha Sil and Vivec, who were three mortals that ascended to godhood. Due to circumstances of their ascension Azura cursed the entire Chimer people into Dunmer. Their skin turned ash-grey instead of golden and their eyes burned red. Their region is goverend by the Great Houses and each Great House has a part of the region that they call their own. The House in the southermost regions are known for slavery of the Argonians and Khajiit. At the time of Skyrim, they have suffered an immense volcanic eruption that destroyed a big part of their land, and their living gods are dead.
Imperials are the human race from the heartland of the continent, Cyrodiil. They were originally diverse tribes of humans that were enslaved by the Ayleids, a race of elves that once dominated the heartland. In ancient times the slaves rebelled against their elven overlords and drove them out or into extinction, after which the heartland became a human controlled region and has since been the seat of several empires. The Imperials of today are divided between hardy Colovians and noble Nibenese. The Imperial pantheon was invented by Alessia the Slave Queen and was meant to incorporate both the elven aspects they had worshipped as slaves and the Nordic pantheon of their Nord compatriots who had helped them throw off the elves. The result was the eight divines, with Akatosh the Time God as the prime deity.
Khajiit are the cat people and according to myths created from Aldmeri stock, meaning they were originally elves. They hail from a region to the south called Elsweyr. There are sixteen different types of Khajiit, although we only ever see one specific type in each of the main games. They worship the moons whose phases determine what type of Khajiit will be born, but they also worship Azurah who created the Khajiit in the first place. Khajiit are looked down upon by many of the other races as thieves and druggies, and the Dunmer use them as slaves.
Nords are the people of Skyrim. They came from Atmora, a frozen continent to the north, and made Skyrim their new home. At first they got along with the elves of the region, the Falmer, but then war broke out with culminated in the genocide of the elves as the Nords took Skyrim for themselves. They have since been involved with every single human empire on Tamriel.
Orcs may be cursed elves, or they may be part of the goblin-ken, stories diverge. The most prominently accepted account among fans is that the orcs were elves who were transformed into orcs when their god Trinimac turned into Malacath. In the older games orcs weren't accepted as an intelligent race, and they were viewed like little more than goblins by the other races. The ending of Daggerfall changed that. Traditionally they live in strongholds where the chief is the only male who's allowed to father offspring. He has multiple wives and the son who bests him in combat and kills him will one day take over as the chief. The wise woman is usually the chief's mother. They are strong warriors and many serve as mercenaries in the Imperial legions.
Finally, Redguards are the youngest race on Tamriel. They arrived in the First Era (Skyrim takes place in the Fourth) after their continent of Yokuda, to the West, sank into the ocean after a devastating civil war. Their strongest warriors of history are called Ansei and they were known to have the ability to summon a Shehai, or a spirit sword, which was basically them summoning forth a part of their own souls and fashioning it into the shape of a sword which could then be wielded. This ability was rare even in ancient times, and has been pretty much unheard of since the Second Era.
This is all very basic and there's a lot more to be said for each race, but this post is already long enough.