Forgotten Realms

Forgotten Realms is an official Dungeons and Dragons campaign setting created by Ed Greenwood circa 1967 for his little stories, but was not part of the official Wizards of the Coast lineup until 1987 and has since been supported by WotC through all five editions of the game. The setting is supported by hundreds of novels' worth of lore by dozens of authors.

Setting

Set on the planet Abeir-Toril, most of the Forgotten Realms source material focuses on the continent Faerûn. Faerûn is pretty similar to pre-industrial Europe, with the exceptions of all of that crazy fantasy stuff. There is a plethora of nations, kingdoms, organizations, deities, and fully fleshed out NPCs who are ripe with political intrigue and conflict. There is absolutely nothing on Toril that has not been fully fleshed out, so there is very, very little room for your own stuff.

Even WoTC thought that this had gotten really out of hand: when 4th edition rolled along, they decided to give the place a reboot. Hey, the Time of Troubles worked for the 1e-to-2e shift, right? They came up with the idea of "the Spellplague": killing Mystara off through the machinations of her long-time enemy Cyric and triggering another massive magical upheaval, similar to the one that had ended the Age of Magic when Mystryl had been killed off. They then skipped time forward a century, to add icing to the cake, presenting a rebuilding world and retconning Abeir-Toril from being the planet's almost never used full name (so it'd be first in the setting encyclopedia) to to being twin planets, with Abeir, under the dominion of the Primordials, serving as an origin for 4th edition races.

Unfortunately... the result was an absolute PR nightmare. The dramatic changes in everything from geology to cosmology, with the World Tree replaced by the World Axis, just infuriated the setting's fandom, who have something of a reputation as obsessive-compulsive grognards even by the standards of the D&D fandom.

Not surprisingly, when the edition change rolled out, a new apocalyptic makeover, the Sundering, was used alongside a 10 year skip to change things more back to the way they were. Although, on the plus side, a lot of the uber-NPCs who didn't have huge fanbases actually stayed dead - they even killed off some more of Mystara's Chosen during the Sundering.

All in all, Forgotten Realms is the ultimate skub setting of D&D, with people still bitching over every little change from 1st edition onwards. Ironically, 5e's attempt at focusing attention on the Realms has begun making it even less popular, as by this point most of the fandom is getting well and truly sick that one setting is getting all the 5e love.

You'll notice going down that a lot of the sub-settings in particular seem to rip-off of real-world places and people. Well, that's intentional: Forgotten Realms was designed with the idea that it has long had secret portals to our real world throughout history - which may or may not have anything to do with the D&D Cartoon. So, a lot of shit in Forgotten Realms is literally supposed to have either been brought there from earth, or inspired earth by slipping through the portals. Mulhurond, for example, is not only "Ancient Egypt in D&D with the Egyptian Gods ruling it", but is by its fluff actually populated by the descendants of Ancient Egyptians who were sucked through portals into the Realms and enslaved by evil wizards.

Faerûn

Medieval/Renaissance Europe/Near East/Africa. The setting of the vast majority of D&D stories, including those of a certain dark elf, to top it all off with the center of attention in D&D videogames to boot. This setting provided inspiration for most of the 3e splatbooks.

Shining South

Pseudo-Africa and Pseudo-India, in that it's mostly covered in tropical jungles and swamps, with one huge-ass desert. Notable regions include Halruaa, an isolationist magocracy, and the halfling homeland of Luiren. Is home to Faerun's native population of thri-kreen.

Unapproachable East

Eastern Asia, a blend of Mongolian, Russian, Indian and Chinese traits. Most famous for being the lands covering Thay, the biggest civilization of evil wizards in the setting, and the more obscure land of Rasheman, which is sort of Russian berserker country but which everyone knows because it's the homeland of Minsc.

Hordelands

The Eurasian Steppes, with Tibet thrown in as well, and yes they had their own version of Genghis motherfucking Khan and mongol invasions. Didn't get updated for 3e, but bits got included in a Dragon article for 4e.

Kara-Tur

Ancient China/Japan/Korea. Updated for 3e with the Book of Weeaboo Fightan Magic and Oriental Adventures, but never updated for 4e as a setting. Little bits of it was included in Dragon for 4e, covering Samurai and Ninja and horde themes as well as new monk stuff and Hengeyokai as a race.

Malatra

Ancient India/Southeast Asia. Got its own living campaign at the end of 2e and the beginning of 3e, and was soon forgotten afterwards.

Maztica

Pre-Columbian South/Central America, the subject of the eponymous splatbook for AD&D. Was not updated for 3rd Edition, but skipped a generation and got an update for 4th Edition. In the form of being replaced by the continent of Abeir and having everything about it shunted into another universe. Wasn't in 3e either so fuck them. Manages to be the skubbiest aspect of the setting; some adore it for being South American Fantasy, a rare thing, others hate it for being so transparently "the Aztec world shunted into the Forgotten Realms".

Anchorome

Pre-Columbian North America. What's written about is based on the Native Americans of the Four Corners cultures.

Katashaka

Despite being located south of not!Central America, it's supposed to be based on Pre-Colonial Africa, and that is literally all that is known.

Osse

Pre-Colonial Australia. That's largely all that's known.

Zakhara

Medieval Middle East/Hollywood Arabia. Left to hang in the wind after 2e ended, save some 3e articles in Dragon Magazine, and probably not likely to come back any time soon. But 5e did bring back the yakmen.

Abeir

Home to the Dragonborn and primordial elementals, as well as all the new sub-giant races and whatever else was introduced in 4e. Ruled over by evil draconic overlords, barring a few kingdoms founded by rebellious giants and humans. Oh, and some weird undead empire that has magical undead-only portals connecting to all graveyards and mausoleums and crypts on Toril, which they claim as their territory.

Abridged History

Creation

Ao creates the twin sister deities Shar and Selûne. Shar is darkity darkness levels of evil and Selûne isn't. So naturally they hate each other. They swirl around in the void that is Realmspace for gods know how long until via catfighting, they accidentally create Toril and create a couple of gods, mainly Chauntea and Mystryl. The latter going on to die several times and become Mystra Because she's a woman who couldn't fucking balance the byproduct of her creation, the Weave, which is the source of all magic, both Arcane and Divine. Things just got out of hand after that and next thing you know, you've got your campaign setting.

Karsus's Folly

In -339 DR an archwizard named Karsus attempts to save the Netheril Empire by making the only 12th level spell in existence- presumably. The spell robbbed Mystryl of her powers and magic for a short time and was really awesome, but then magic goes wild because a fucking epic-level caster does not equate to a level-uncapped deity that handles fucking magic everywhere. In short Karsus ruined everything for everybody on that day. Lucky Mystryl was there to sacrifice herself and put all of her powers into a young female wizard and rose again as Mystra. Marking the first in the goddess's long line of deaths and rebirths. This sparked all the shit that went down in the game Neverwinter Nights 2, and is the reason why Magic sort of meets a cap.

Times of Troubles

The Times of Troubles, also known as the Avatar Crisis, started in 1358 DR when the two deities Bane and Myrkul thought it would be a great idea to steal the Tablets of Fate from the overdeity Ao. As punishment Ao banishes all of the gods to walk on Toril as mortals (except for Helm who was to guard the gateway back into the heavens) until whoever stole them felt bad and returned them. During this time Mystra got some of her power back and thought it would be a brilliant idea to challenge Helm to get back into the heavens. Helm wouldn't have any of it and and bitch slapped her down the Celestial Stairway. She hit the bottom and died in an explosion of magic. Eventually some mortals, Midnight (who went on to be the next Mystra), Kelemvor, Cyric, and Adon of Sune, fixed everything and they got be gods for a reward. Except for Adon of Sune, he really got the short end of the stick on the loot table for that encounter. He lost faith in Mystra, committed suicide, then got his faith back and went on to frolic in the brothel in the sky. This even signaled the change from AD&D 1e to the second edition and magic changed in real time in correspondence to these events, depicted in the canon Forgotten Realms Comic book series, featuring Bruce Campell as an Ex-drug addict halfling, an ex-alcoholic Paladin, an Elf with expressions that would put the Laughing elf to shame, a hot golem, and other goodies.

The Spellplague

In 1385 DR the goddess Shar had the god Cyric stab the goddess of magic Mystra. This caused giant pillars of blue fire to ravage Toril, killing untold masses and driving most wizards to madness. One of the few wizards to be unaffected by the event is Szass Tam, who continues to be a badass by turning into an uber-powerful lich, seizing control over Thay, and killing off almost everybody there to create a fuck-huge kingdom of the undead. To make matters worse, unlike the previous times Mystra has died she couldn't reincarnate, a stunning development that "changes the rules of magic" which translates as another real-time spell-casting change for 4e rules, just like what happened in the Time of Trouble. Parts of the planet end up either destroyed or switching places with parts of the land from Abeir. Elminster lost his special status and all his powers, and most of his Chosen buddies wound up dead. The Pantheon was reshuffled, tieflings changed to match the new unified tiefling look, and the World Tree was reshaped into the World Axis. It was a huge upheaval.

The Sundering

In 1485, the worlds of Abeir and Toril split apart again, as WoTC tried to deseperately bring back the Faerun grognards by retconning the Spellplague. It turns out being stabbed wasn't in fact enough to kill Mystra, she was just hungry and had wandered off to find a cheeseburger made of her own children. Abeir went back to where it belonged and several other dead gods who were deemed superfluous suddenly came back to life.

This event was known as the 'Sundering' but the writers didn't want to piss off the fans, so they held off explaining what the fuck happened until the fans could tell them what, in their opinion, should have happened. While waiting to be told how to do their jobs, dragons attacked everyone, trying to rescue Tiamat from Hell where she had in fact NOT been since before the Spellplague but because she was there in every other setting, we're all supposed to pretend that she was, so mighty adventurers can stop her from escaping in a linear story which was easier than the likes of the first time this asspull was pulled with Bloodstone Pass, Fuck you Bahamut.

From there, various other intersecting adventure modules happened at roughly the same time, and since things were mostly back to the pre-4e days everyone was happy. Except dragonborn fans (and dragonborn, whatever you think of them, are still a damn core race), as the writers quickly killed almost all of them off, crammed them into a tiny reservation, and have yet to make a single dragonborn NPC for any adventure module yet released, just to rub salt in the wound. None the less, many grognards still balk at the return of several 4th edition era elements, such as including the Shadowfell and the Feywild in the Great Wheel. But, appeasing the old guard is ridiculously hard anyway.

Interesting Side Notes

• Drizzt will outlive all of his friends and he cries about this often until they fixed it.
• There was a time Drizzt was bearable, until all of his adventures amounted to the power of friendship and his magical power of secretly Lolth's blessing empowering him into a murderhobo edge lord that got so broken he BEAT FUCKING DEMOGORGON with the power of an anime power-up one shot asspull to SAVE THE UNDERDARK
• The Neverwinter Online scenario of this event had the Demon Prince smack him and his party straight into an Abyssal rift, after the generic shounen speech of the power of friendship which is a great way to retcon this entire event for a ranger beating a monster so hard to kill based on how much it can throw at a party in summon-spam alone, nevermind the threat the creature itself actually poses.
• Elminster has sex with Elvira who is polymorphed into a man. He also was turned into a woman once, he's effectively, a massive fucking degenerate that hasn't been killed off because plot Armour and horribly oppressive "good" organization of spies, scouts, and adventurers he tricks into doing his work for him, he also advertises Faerun as anything but a clusterfuck continent so full, it feels more like the description of the endless murderfest an MMORPG provides over an actual living setting.
• Szass Tam is fucking awesome and basically Ming the Merciless in D&D.
• Larloch, Feared Master of the Warlock's Crypt, is one of the few statted NPCs representative of a finalized epic-level minmaxed PC wizard, with so much shit in his arsenal he ranks as a DMPC in his own right. He's also (with a little bit of Szass Tam) the inspiration for the character of Ainz Ooal Gown from Overlord.
• Tempus, the badass bro jock god of battle.
• The world goes to hell in the 4th edition.
• After apparently being killed by one of his only friends, the god Helm survived the Spellplague in the form of a goat.
• The first 3-D CRPG was set in FR.
• Jarlaxle the dashing drow mercenary had a three way with twin copper dragon sisters named Tazmikella and Ilnezhra.
• Khelben Blackstaff has a fear of Lawyers and will do ANYTHING in his powers to avoid them, even resorting to elaborate illusions of unwanted marital scenarios to avoid lawsuits from extraplanar entities (I am not making this up)
• The setting is so high magic that even before the current established era in 3.5 and onward, even back in Ancient Netheril, there were FUCKING LICHES EVERYWHERE.
• The God of Vampires does not give a fuck, do not try to make him, he will just try to eat you and fuck with you on his layer of the Abyss.
• His high priest fucks Lolth, and this is the reason why Drow like vampires so much
• The last time a vampire gave a shit in FR, he nearly conquered Baldur's Gate itself solo, but got his ass kicked because he went ahead of a forty-thousand undead strong army with a macguffin that literally made him an Elder Evil, by technicality of demigod level strength which would have been even more broken anyway as he was a base vampire + vampire Lord
• Minsc was petrified, turned into stone, and kept preserved until marketing would call upon him again for a lackluster comic book series that is only good for shilling 5th edition products as bad as Neverwinter Online did and Siege of Dragonspear

Forgotten Realms And Sex

The current Forgotten Realms material is highly sanitized from Ed's original vision. In FR as created by Ed:

• Bi-sexuality is normal (and yes, this means the men as well as the women)
• "Revels" (sex orgies) are normal
• "Festhalls" (brothels) are in every small village and visiting them is normal way to spend evening.
• Prostitution is the main industry of Forgotten Realms, "sex workers" are everywhere and there are about 100 different names for different kinds of prostitutes.
• Incest is normal way for families to "indulge feelings of mutual affection"
• Public city-wide orgies are the way to celebrate major holidays

All of this is confirmed by Ed Greenwood himself, from Ed's responses to fan queries on the Candlekeep forum. So Saith Ed here, here, and here. It's also all completely, 100% canon thanks to Ed's ludicrously favorable contract; other writers can try to dance around the creepy shit, but they can't outright contradict anything or else the whole setting falls into Ed's greasy, sticky hands.

Of course, this isn't exactly out of place in certain historical periods and cultures (Greeks, in particular the Etruscans, were known for having frequent orgies and the nobility of many cultures like Hawaiians and the Ptolemy Egyptians practiced sibling incest so as to aviod muddling the bloodline with peasant genome; Rome had all of the above at various points), so some individual cultures or nations with this going on probably wouldn't be off the mark... but when the whole damn world is into this stuff, then clearly the author has something on his mind.

In short, the Forgotten Realms are Ed Greenwood's magical realm cleaned up by TSR and later Hasbro for general consumption, and the Romantic Encounters mod for Baldur's Gate is probably canon.