"In Plain English" this is a review of the game world.
A quick and  dirty reveal of the essential story facts.

1. The world used to be Awesome. Or so people claim. Pretty much all of the "Happy and tolerant federations of powerful good people working to convert the misunderstood selfish people and standing in firm opposition to the perverse, ugliness of True Evil" that were spoken of [any type published material] did exist once upon a time. Hot and cold running blonds, glittery fairies, flighty elves, pure unicorns, pretty butterflies, curmudgeonly dwarves, flatulent halflings, the best part of every fanciful, whimsical, myth of merriment and riches. [And people have being making up stories about it ever since.]

2. Then Boom! All of that comes to an end in a great upheaval collectively known as The Cataclysm.   Various hair-trigger tenuous peace treaties fell apart with predictable results. Fragile economies crash. Systems of Law fail to control the resulting degradation of societal mores and community control. Whole nations begin to use their strongest means of both creating and controlling the widespread resulting destruction. Fire and brimstone coming down from the skies! Rivers and seas boiling! Forty years of darkness! Earthquakes, volcanoes.  The dead rising from the grave. Human sacrifice, Dogs and Cats living together... Mass hysteria!
Real end of the world type stuff.

3. The world suffers through a Dark Age. Years unnumbered passed in barbarism and savagery - where those who had individual personal power or access to it typically through a magical items ruled through terrorism, domination, and brutality. Eventually the social evolution of civilization began to return when wars were again fought by hordes subsumed into clans, tribes, nations, and finally empires. Humanity clawing its way into the light of reason but distinctly more cynical for the experience of having done so.

4. There's a real disparity in power among the races. The majority of the world is an agrarian society. In order to deal with the bleakness and the fear and the war and the horrible shit that can happen to anyone who may not be protected by a Noble Lord. People make up stuff that happened in the Age of Dreams. You know? All that great stuff before the Fall... when everything was awesome?!? - (See point 1.)

5. Sometimes the things that go bump in the night cannot be attributed to an overactive imagination. There were a lot of things that were conquered, imprisoned, or over-shadowed by the power of the Gods BEFORE the cataclysm - that are a real threat now. And, they've been growing in power for a long time without anyone to limit them... or to tell them to behave.

6. The Gods had less presence here and now than they did before the fall of civilization. Although stories of people who had the power of simple cleric is a persistent myth and everyone has got a story ... a friend of a friend that saw one with their own eyes performing a miracle.  No one you know has actually ever MET a true cleric themselves. - Neither CLERICS nor ORACLES are available classes at this time. Although Questioners (inquisitors) and Druids  can give you scope of what a Cleric might be able to do.

7. All of the known (standard) races have become more clannish. And with only one notable exception (Elves), all of them are integrated into the pervasive human culture. Some of the once 'half breed' races have collected sufficient unique traditions to become their own discrete societies. No true elf has been seen by any human village in centuries.

7a. Half elves have assumed an aggregate cultural identity. Calling themselves the Ikkosi they have become a semi-nomadic tribal fellowship.  Ikkosi have a reputation as deadly archers and accomplished equestrians and many gain employment as mercenaries - advancing their culture among other peoples. Their most valued crafts include the making of musical instruments, carpets of colorful and intricate design, and the production of silk of which they have a near monopoly.

7b. Half-Orcs have undergone the most divergent racial changes from the standard.. Now known as Ogrun, this race was eugenically evolved at a rapid pace over a thousand years by the arcane might of the Jotun Empire. The Apparent end of the Giants and their Empire is fabled in story and song - the Ogrun alone may know the Truth within the Myth.

7c. The traditional Dwarven mountain homelands of yore were lost during the reshaping of the world.  Instead of hopelessly attempting to resurrecting them, the remaining clans have sought the return of civilization by stabilizing Human Society during the last thousand years.  Now, if a Kingdom has Dwarves within it at all, they will reside in an isolated but well respected Dwarven ghetto. Houses and shops built to their own exacting standards. Dwarves have a heavy presence in Craft Guilds, Mercantile Unions, and more recently city politics. Although they do conspicuously avoid direct national or kingdom governance, believing that humanity requires its own measure of independence.

7d.  Elves have had a philosophical civil war which no other race really understands the specifics and has become subject to modern fable. The appearance of a 'True' Elf hasn't been seen anywhere for centuries.  And should an Elf suddenly appear reactions would vary between alarmed wonder and covert hostility largely due the heighten level of nonhuman intolerance this generation.

7e. Halfling, or Yutani, society is isolated on the far western archipelago, forcing this race to become natively seafaring to survive.  So well have they adapted to this adventuresome profession they have become a feature of many coastal towns - their true homeland is subject to homespun 'tall'-tales by landlubbers.

7f. Humanity is the dominant race. Humans are only separated in attitude and philosophy by regional culture. There are 8 human cultures in the "Central Empire" - each varied by technology, philosophy, and tradition but NOT by Law. Imperial Law is maintained by Legates and Lords; and enforced by Praetors, Sentries, Wardens, Lawkeepers, and Magistrates.

8. Magic is blamed for the Cataclysm.
Open Magic use is feared to one degree or another by the general public. Sophisticated and cosmopolitan INDIVIDUALS may be exempt from this ubiquitous belief... but openly casting or using an obvious magic item in public is just as likely to get you cast as a villain by any civic leader who may demand you be drowned to protect the village from your demon worshiping ways.

9. They ain't wrong.
It doesn't help any attempt to mandate control over the populace to accept specific magic users as peaceful and helpful if there really are powerful demon worshiping cultists who occasionally disguise themselves as benign.

10. Miraculous powers are the domain of the Faithful... sort of.
Magic exists and may pursued although there is a necessity to hide any reality altering ability to varying degrees depending on the nature of the spell.

10a. The camouflage provided by the miraculous is easily the most effective disguise, but papal authority has the means to castigate the independently minded 'priest'. Including expulsion and excommunication, making 'outed' clerics even more hated than cultists.  The church might have started as a good place to hide from the wrath of Mob... but after a millennia the Imperial Pantheon is a guild of considerable power and ACTUAL BELIEF.

10b. There are classes which cast divine magics but whose own celestial mandates preclude papal governance. Thus - an inquisitor, ranger, or paladin may not assume a priestly role. While they may dispense advice and often serve as paragons of exemplary behavior, by class - they are not directly subject to edicts of the Papal Authority. The Church may enter binding agreements with individuals - each class remains subject to their own superseding authority.

10c. For better or worse, proof that the men and women 'called' to shepherd the congregation have actual divine inspiration depends on FAITH alone.

11. Powerful Artifacts were dispersed into the open, by the collapse of the old empire. At the edge of the frontier there is a ring of doorways/gate ways/ portals. As a free bit of Player Character Lore you are aware - these apparently separate and distinctly described monuments are all connected as parts of ONE ARTIFACT. Some of these doorways are active, others are closed, all of them contain the means for anyone that walks through them to go ...Elsewhere?