Basic Scarterra Primer

Scarterra is a fantasy world with a detailed cosmology of gods and cosmic events setting the framework for high fantasy adventures both in fiction and in RPGs. Scarterra uses a so-called "Kitchen Sink" approach to fantasy drawing inspiration and elements from many different historical and fictional sources associated with the fantasy genre but the bedrock of Scarterra's lore is based on the cosmology loosely inspired by the barely functional pantheon families of Ancient Greek myth.

History of Scarterra in broad strokes

The current gods known as the Nine, and they have ruled the universe ever since overthrowing their tyrannical progenitor during the Divine Rebellion.
The Nine collectively created dragons to be the dominant race during The First Age. A few of the Nine independently made other races as a personal projects. Everything was going good until constant conflict between nations pushed a dragon queen to tamper with forces beyond her ken accidentally destroyed most of the known world in what was called the First Unmaking .
The Nine hit the reset button and collectively made elves to be the new dominant race during the the Second Age. A few of the Nine made other races as personal projects. Everything was going good until constant conflict between nations pushed an elf king to tamper with forces beyond her ken and accidentally destroyed most of the known world in what Second Unmaking.
The Nine hit the reset button and collectively created humans to be the new dominant race during the Third Age , the current Age. A few of the Nine made other races as personal projects and the world is now quite crowded with the surviving remnants from previous ages. As the various human and non-human factions compete for resources, everyone is aware of the disasters that occurred before, so there is definitely probably not a chance someone will destroy the world again.

Magic and the gods

Composite Display of the Nine's portraits by Zeta Gardner

Every tribe, every nation, every intelligent species more or less agrees on the existence of the same nine deities. What they don't agree with is the correct way to worship them.
The Nine are active deities and though they don't make giant displays of divine power often, they interact with the mortal plane in many small ways every day acting through the theurgists (divine spellcasters), oracles, and spirits (extra planar servants of the Nine).
At best, the Nine operate like a largely dysfunctional family. At worst, the Nine operate like a Byzantine group of frienemies with ever shifting alliances, enmities and betrayals. The Nine's actions among themselves tend to bleed into the actions of their most fervent worshipers and visa versa. This is not the sole driver of conflict in Scarterra but it's an everpresent undercurrent that flavors all existing politics and associated political conflicts.
When it comes to how ordinary mortals worship the Nine, it is a careful balancing act almost trying to appease nine separate kings and queens at once.

About 1% of mortals have some kind of magical ability. Roughly half of all magic is divine in origin and roughly half is arcane in origin. Arcane magic is better at some things and divine magic is better at other things. There is also a lot of overlap between them. But the difference is that divine magic channels of portion of Nine's power and arcane magic involves manipulating complex metaphysical laws of the universe that even the Nine are beholden to. Most Scarterrans do not understand or care about the difference.
Some creatures have special abilities or advanced that we in the real world would consider supernatural, but within the culture and understanding of Scarterrans, this is not magical, though it is special. This includes but is not limited to spirit loas, alchemy, and creatures flying with wings that don't look like they are strong enough to create lift.
The relatively high number of magic users a huge impact on the economics of politics of Scarterra but while magic is relatively common, powerful magic remains fairly rare. Magic is not powerful enough to upend basic elements of a medieval setting. Most Scarterrans make their living from either farming or selling goods and services to farmers. Most places uses a precious metal currency. Travel between distant places is fairly slow and unreliable Most ruling elites either have a castle or a want a castle.

Creatures of Scarterra

I use the short-term "mortal" to refer to sapient living creatures with souls and "beast" to refer to sentient living creatures without souls. Scarterra has lots of monsters and extra-planar entities of varied types but the core of the conflicts that drive most stories are humanoid mortals fighting humanoid mortals.
Humans are the politically and numerically dominant mortal race on Scarterra, but they have to share the world with many other intelligent species, some integrated with humans, some hostile to them.
Most fans of the fantasy genre should be very familiar with some of Scarterra's fantasy races including but not limited to races such as elves, dwarves, dragons, and goblins which only have minor tweaks in their cultures and backgrounds to fit with Scarterra.
Some of Scarterra's fantasy races put a unique twist on the old fantasy tropes, but keep the core concept mostly intact. This includes but is not limited to gnomes, kobolds, satyrs, grootslangs, and umpteen half-whatevers.
Some of Scarterra's fantasy races are original creations or they alter the original concept so much they are barely recognizable from their roots including but not limited to kalazotz, camazotz, and tengku, Death Goats, and Void demons.
The humans and demihumans of Scarterra are not like stereotypical old school fantasy where damn near all of the the fantasy humans from another world inexplicably resemble Western Europeans. Nor does Scarterra follow the "modern" fantasy stereotype where every separate nation inexplicably resemble has the same mix of people that resemble a random cross section of southern Californians.
Scarterran mortals have something called elemental ethnicity. Elemental ethnic traits are mostly cosmetic and do not bestow anyone with exotic supernatural powers. There are no "benders" in Scarterra.

Eight commissioned human portraits by Diana Rahfoth

People near large bodies of water tend to have "watery" traits, people inland tend to have "earthy" ethnicity traits. People from warm areas tend to have "fiery". People form cold areas tend to "airy" traits. If people are from an area with multiple elemental influences or if two people of different elemental ethnicity have a baby together, a Scarterran will have visible traits of more than one element and a majority of Scarterrans of mixed elemental heritage.
The net result is that while Scarterrans as a whole come in a wide variety of body types, hair colors, and skin tones, most people look fairly similar to their neighbors.

Alternate Settings within Scarterra

All of these alternate settings are still works in progress.
Scaraqua, the realm of the sea, is both in the same world as Scarterra and a second world altogether. They have the same laws of physics and metaphysics but have different myths and cultures. They even ascribe different names and personalities to the Nine. Both Scarterrans and Scaraquans drastically underestimate just how large and diverse their sister realm is.
Scarnoctis is a subterranean realm similar in core concept to the Underdark of D&D's Forgotten Realms and the Hollow Earth of early twentieth century science fiction.
The Red Era is a sort of a "prequel" time period for Scarterra. The intent is for Red Era stories to have a more Sword and Sorcery feel as opposed to the "default" Feudal Era stories which aim for a classical high fantasy feel.
Fae Home is a parallel plane of existence home to the Fair Folk and other fae creatures. Sometimes a mortals travels there for a Alice in Wonder or Stardust type adventure but Fae are more likely to visit the mortal plane rather than mortals visiting Fae Home.