Entire cities of humanoids were cast into the earth. Enemy armies were attacked with bombs of light that banished them to the depths in dozens of newly formed dungeons. The threat of condemnation became the favorite tool of the Holy Order of the Inquisition. Those orcs, goblinoids and such who remained on the surface were forced into servitude. The promise of banishment keeps them in line.
As the years went on, the "winners" began to feel a sense of boredom. So they would pit themselves against the dungeons. And if a dungeon became too lethal, they would send in the Inquisitors to destroy the man-made Binding Stones within, which would instantly destroy those bound to it. The denizens of the dungeons were soon educated to know they were nothing more than a diversion for their masters on the surface. Goblins and orcs were slaughtered for training. The demons and devils faced different but no less terrible fates.
But in all this time, the location of the original Binding Stone has been lost. The dungeons grow with each new bound creature and have become a winding entangled maze of underdark domains. Bored nobles and adventurers continue to explore the depths. But they don't venture too deep. The most powerful creatures are buried there. And the Inquisition has declared the lowest depths to be "at your own risk". As long as the creatures stay down there, the Holy Order does not hunt them or destroy their home.
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Today the people of the surface have settled on a stagnant lifestyle of pure peace. No wars, no temptation, almost no drive to do more. The vast majority are content in this life. But there are still adventurers and others who wish to become more than content with life and brave the depths of the dungeons.
There is also Syrafin, the Succubus. With her Master banished right before her, she was left desolate. Most succubi who were not banished with the rest of the demons were forced to work in brothels or become concubines for the wealthy. But such work was not easy for her. Cursed for her master's pleasures, her maidenhood returns with each dawn. And unlike her Lord, the humans and elves hardly made it worth her pain. So, she became chaste and resentful. All the while exploring the dungeons, looking for signs or clues. Any way to reunite with her Master. Sometimes alone or with a party, she spends her eternal existence searching.
Then there is Fillindari, the lone survivor of the original expedition to seal the Demon away. She was blessed with eternal youth and life, beyond any human before her. She will be eighteen forever. Having witnessed her entire company fall to seduction and temptation, while she alone remained pure, her life has been one of adoring loneliness. Everyone sings her praises even as they stay away from her. After all, if she survived and resisted the Dark Lord, who are they to touch her? Leaving her yearning for more than what has become her lot in life. But her divinely blessed radiance instills the hands-off mandate on even strangers who would approach her. Only a god could kill her now, or free her from her curse. The Gods of Light view it as a blessing to be carried by their champion and refuse her pleas. There is only one who might listen...
