Those born in the earth court have the ability to wield the earth element. They can make plants, flowers, and trees  grow from the earth, but they can also use their powers as a weapon.

Those born in the fire court have the ability to wield the fire element. They can make fire appear in many forms: balls, rings, walls, lines, and many other shapes. They also are the only court to have dragons, who they view as their enemies.

Those born in the water court have the ability to wield the water element. They are able to command both salt and fresh water. They also have a special connection with sea creatures, including sirens, who tend to be vicious and deadly.

Those born in the frost court are able to manipulate and create ice, snow, and frost—any of the winter elements. They are located in the northern part of the continent, where it's a perpetual winter.

Those born in the sky court have the ability to wield wind and are the only ones whose magic manifests in a physical form: as wings. They can fly, and they can also control the wind. Unlike everyone else, they live high up in the mountains on isles that are hard to get to without the ability to fly.

Ever since they attacked Arathia and waged war, the shadow court has not been acknowledged as part of the continent. They have been banished to their island, unable to leave and mostly silent since they lost the war they started. Shadow people have the ability to steal people's shadows and control the shadows to do their bidding.

The star court no longer exists. Sixty years before the start of book one, Sorrengard attacked Arathia and wiped the star court from existence, killing everyone who lived there. Now, all that remains is the Deadlands, a terrifying place full of monsters and criminals. No one willingly travels to the Deadlands, and anyone who does rarely is heard from again.

Everyone in Arathia worships the seven spirits: Earth, Water, Fire, Frost, Sky, Star, and Shadow, whom they believe give them their powers.
There are two periods of time known in Arathia: the Old World and the New World. Not much is known about the Old World, other than a few things. Its people had the same elemental powers as the people of the New World, its people worshipped the same spirits, and that the spirits regularly appeared to and interaction with the people of the Old World. An unknown conflict or force wiped those of the Old World from existence. There are theories about what might have happened, but nothing concrete. Everything the New World knows of the Old World is through historical documents and findings.
The second period of time, the New World, started hundreds of years prior to book one when seven brave humans left the human lands in search of something better than the lawless, corrupt continents where they lived. They stumbled upon Arathia, an undiscovered place where they each began to manifest different powers that they eventually realized must have come from the seven spirits. Those seven humans became the original rulers of the courts and are whom the current rulers are descended from.