This world once held the center and source of all magic. None who remain on the world know or remember this. A world of vast oceans and a singular continent that held the magical Kingdom of Solace. In this kingdom was the fountain of mana, the source of all-magic. The opinions over who should have access to this source led to a war. Any record of what happened next is lost. What is known is the Grand Sundering followed.
The Grand Sundering was the unnatural formation of the Grand Scar, a massive geological fissure that spans nearly half the equator of the world. Geologic markers show that massive oceans drained into the center of the world as the Grand Scar formed. The massive gravitational shift pushed most remaining surface water to the poles, where it froze solid. The surface was pushed and pulled and eerie and dangerous land formations remain.
None survived the massive changes across the world. Wild-magic remnants world sometimes pull random people and creatures to the wastelands. Not many survived, but over countless millennia of these random occurrences there began a small colony. of sorts. A powerful wild-magic Sorcerer calling himself 'The Grandmaster" built the first Arena-World. He exploited those who collected here to build a massive arena complex in the center of the planet, on a large plateau. He employed wizards to teleport spectators and gamblers to view the games and became wealthy enough to claim dominion over several realms.
That is until a young protégé of his killed him and took over. The Grandmaster had led his Arena-World for hundreds of years, enough for the world's culture to change towards serving the Arena Battles. The newly appointed Grand Leader refocused this cultural engine to create he own vision of the Grand Arena. Instead of wizards she discovered stable portal magic and expanded the worlds that could access the Grand Arena, expanding the profits to unbelievable levels. The world outside The Grand Arena has remained a wasteland and barren, allowing insanely difficult beasts to evolve. Inside the Arena is one of the most profitable combat arenas in the near cosmos. This distinction has come with the slight notice of some Gods. These gods have noticed that most Grand Arena Champions are worthy to face in an arena of their own.
The Grand Leader also created water-creation magics which is the main reason none have ever attempted to usurp her in her thousand-year reign. Her ability to maintain the stability of the Magical Spring, which supplies the entire Grand Arena Complex with plentiful fresh and potable water, keeps her solidly in power. Her stable-portal magics giving access of countless worlds for import also solidifies this power. Although she is harsh and pragmatic, she is rarely ever cruel, but has shown cruelty in the last thousand years. Enough to maintain fear. Her ability that maintains a livable complex on this otherwise inhospitable world has turned the Grand Leader into a near-divine idol from many who dwell, work, and serve the Grand Arena.
The Grand Leader maintains a strict Import control over her portals ensuring her technology remains the most advanced on the world. Some portals can destroy advanced tech immediately. Others will merely sound an alarm, letting the sentries retrieve the offending technology. The area around the Grand Arena is patrolled by sentry-bots ensuring nobody unauthorized leaves. The inclusion of the sentry-bots is overkill because the wasted world has very little chance of survival anyways.
The Grand Arena is known in most worlds that have high-rolling gamblers and magics strong enough to create portals. This knowledge comes with reverence for the powers that the Grand Leader must have to maintain such an entertainment venue for such a long time.
(Hidden Lore: The Grand Sundering)
The War of Mana was indeed over who could access and gain the powers of the font of all-magic. The King knew of its destructive power and held-fast that only a few selected could ever possess the font. Other forces laid siege to the kingdom and when all hope was lost, the King did the unthinkable. He and a small number of Solarian Mages transformed the font of all-magic into a new form, one that would escape the world. The resulting spell created a seed of all-mana, the gravity of which flew into a near-orbit white it tore up land from the planet to form a protective mass. The land which is now the "Floating Forrest" is the land torn from the Grand Scar. The formation of the nearly inaccessible skyward forest destroyed the world in the Grand Sundering. None survived. The citizens who live on the Grand Arena's world are the result of countless millennia of wild-magics pulling random creatures to the wastelands.
(Hidden Lore: The Grand Leader's Cruelty)
Early in her reign of the Grand Arena she realized the growth would overwhelm their ability to keep the Grand Arena clean enough to attract and keep High-Rollers. She gathered weak and poor from several less-than well-off worlds and cast them out into the wastelands. She left them with nothing but the proximity of the exit of her new Grand Arena sewer system. The post-apocalyptic wastelands held no easily accessibly surface water, so this waste was the closest thing the abandoned ones were going to get. The slums outside of the Grand Arena have built up a small but healthy culture processing and recycling the waste from the Grand Arena. These slums sometimes put up resistance or rebellion against the Grand Arena. Sometimes the Grand Leader has put these down with overwhelming force, and sometimes she has quelled the rebellion with deliveries of clean water and crates of food.
Over the past few hundred years the Grand Leader has noticed the high evolution of the native Scavs. She is frightened of what this native race represents and has taken some steps to potentially shut-off or quell this new race.
The Grand Leader once did research into the remaining wolf population, her experiments seemingly caused the extinction of the world's wolf species. (The few remaining just learned to hide really well) The Grand Leader only abandoned her research after she learned the "Way to Paradise" was a way to "remake the world" a feat that, in her mind, she had already accomplished.