The Golden City of Ureh was, at its time, one of the greatest cities in all of Sanctuary, ruled by the judicious and pious Juris Khan, a well-known political figurehead in the region. The people were among the finest, most civilized and culturally advanced for their time. Such was the prosperity of the kingdom-state that it attracted traders, artists and masters in every field to bask in its glory. But, for all its prosperity, it came under the evil gaze of the Lord of Terror, for the people of Ureh did not fear anything let alone be terrorized.
Diablo laid siege to the city in his trademark fashion - corrupting it from within. Although the innocent inhabitants of the city were unaware of what transpired, the city's powerful sorcerers, both indigenous and foreign erected unbreachable barriers that prevented Diablo's influence from spreading within. This caused Diablo to change his tactics, he started corrupting the local flora and fauna, using them as pawns to weaken the barriers that withheld his influence from spreading. But these weak machinations were no match for the arcane powers of Ureh's united sorcerers, bent on protecting the city at all costs. But the people started to suffer, the city was surrounded, supplies stopped.
It was then that Juris Khan had the vision, of the Archangel Mirakodus who told him the will of the High Heavens, that the people of Ureh had not been overlooked by the Heavens, their fight against Diablo and his fiends was soon to be over. The city of Ureh was granted a place in the ultimate sanctuary any mortal could desire, the ethereal planes of the High Heavens themselves. But, Mirakodus laid down a strenuous condition - the way to Heaven was open, but it was Ureh's job to find it.
Juris Khan, a powerful Sorcerer himself, consulted with his advisors, and eventually his people regarding the new events. He initiated his daughter Atanna to see the visions that he had seen. The initial joy that was prevalent was soon replaced by the nerve-wracking search for the way to Heaven, the perfect spell that could transform Ureh into paradise. Mirakodus assisted Juris Khan and his compatriots in their search, and eventually, they found a way.
No stone was left unturned in what was to be done. Juris Khan, and his close aides Father Tobio and Archmage Gregus Mazi at his side started summoning the portal that would lead them to salvation. But then...
The ultimate betrayal was done. Gregus Mazi was allied with Diablo all this time, he sabotaged the spell, causing it to reverse and lead them to not the High Heavens, but the Burning Hells, the realm of the Prime Evils themselves. The sudden change in the spell's configuration caused the spell to drain the life-force of all who cast it, so Gregus Mazi teleported himself outside the city, letting the inhabitants in the city fend for themselves. Juris Khan tried to realign the spell, but the damage was done. The reversing of the spell along with its subsequent realignment caused Ureh to be transported to neither Hell nor Heaven, but in a limbo between the extreme planes. But no one outside the city knew of what actually happened on the fateful day, except Gregus Mazi.
Eventually, Gregus returned to his home-city in order to have his fair share of the prize. He was captured and killed in a way that even the pious Juris Khan regrets uptill now.
This was narrated by the Lord of Ureh himself, Juris Khan, when Quov Tsin, Kentril Dumon and his mercenaries reached his palace. This was supposed to be what happened...
Or so it seems...
It seems, as said by Juris Khan himself, that legends are not always what they seem to be, for while the rest of Sanctuary believed Ureh to have ascended, it had actually found itself between the mortal and immortal planes, neither living nor dead. The events that unfolded were not spoken of by any mortal. That is why, it did not take an immortal Juris Khan to brainwash Kentril and his comrades about the aforementioned real story of Ureh. What actually transpired is as follows.
Diablo had a far more diabolical plan up his sleeve, he disguised himself as the Archangel Mirakodus and corrupted Juris Khan and Atanna with his visions, a captivating thought for any mortal. Eventually, both father and daughter became living vessels of the Lord of Terror, with the Lord Khan actually becoming an embodiment of Diablo, subverted by his will.
The portal spell was never supposed to grant Ureh passage to Heaven, but to Hell, so that the Prime Evils could use the open portal as a means to send the Demonic Legion through to invade Sanctuary, an aim they were granted by the eventual destruction of the Worldstone.
Gregus Mazi was never the traitor he was made out to be. He was the only one who found out the Lord Khan's association with the Dark Lord of Terror, and his reconfiguration of the spell led the city to its intended purpose, towards Heaven, but still draining the life out of the caster. He did not teleport outside the city, but was teleported by Juris Khan, who in his frenzy had all his fellow sorcerers with him.
Gregus Mazi's return to Ureh was to set things right, to destroy the evil that had crept over the Light of Lights. This time, he was not alone however, as Father Tobio assisted him seeing the madness gripping the Lord Khan and his followers. But they were both captured and killed. Gregus was not killed, but was turned into a part of the mountain Nymyr so that he may watch over Ureh as a reluctant guardian.
This is the real story of the Light of Lights, a story of corruption, betrayal and deceit at its finest.