When Sylas shared his thoughts, Mandos was deeply moved.
Arda had never truly had a concept of the Underworld. The Halls of Mandos came closest to filling that role, but they accepted only the souls of Elves, Men, and Dwarves.
The souls of all other creatures and races, upon death, had simply remained in Middle-earth, eventually drifting into whatever shadow of a netherworld existed or fading away entirely. But since Sylas had transformed that netherworld into his sub-space, repurposing it to carry the collective spiritual energy of all conscious beings, even that uncertain refuge was gone. Those souls truly had nowhere left to return.
And if a true Underworld were opened, a separate realm unto itself, the achievement would be comparable to Varda's great act of kindling the stars and opening the vault of the sky. The implications for Mandos himself were equally significant. As lord of the dead, his authority would expand beyond anything it currently encompassed.
"My friend," Mandos said, and there was unmistakable admiration in his voice, "if I did not already know that your power lies in time, I would have taken you for the master of wisdom itself. Your thinking never ceases to amaze me, Sylas."
Vairë nodded beside him, and her agreement was wholehearted.
She had reason to feel that way. It had been Sylas who, some time ago, had pointed her toward expanding her gift for weaving into the domain of fate and destiny. She had not yet fully mastered that power, but she had already grasped enough of it to weave the fate-lines of any being below the level of the Valar.
When she finally claimed it completely, she would stand as the true ruler of destiny, one of the most formidable powers in all of Arda. For that, she owed Sylas a debt she had not forgotten, and she regarded his wisdom with deep and genuine respect.
It was the kind of wisdom, she reflected, that saw what others had not thought to look for.
He had helped the spirit Varda open up the universe and kindle the starry sky, allowing the domain of Arda to expand outward in what amounted to a second act of creation. He had revived the Two Trees of Valinor. He had transcended the boundaries of space, claimed mastery over spiritual power, and used that mastery to defeat the Evil God Ungoliant within his own domain.
Every one of these acts was already woven into the tapestries on the walls of the Halls of Mandos, preserved by Vairë's hand as history of the highest order. And now he was proposing the creation of an entirely new realm for the dead.
To those around him, it seemed impossible that such a mind would not one day claim the mantle of wisdom itself. If there was ever to be a God of Wisdom, they could not imagine who else it might be.
Sylas, for his part, quietly shook his head at the praise.
He did not believe his wisdom truly surpassed that of the Valar. He knew exactly where his advantage came from. He was a transmigrator. He had arrived in this world carrying knowledge of futures and fictions that no native of Arda could possess, and it was that foreknowledge, not any extraordinary depth of mind, that let him offer ideas no one else had considered.
He had never sought authority over wisdom for that reason. He understood, perhaps better than anyone, the true weight of what he actually knew and what he did not.
Still, the proposal had Mandos's full support, and that was what mattered.
The two of them settled in to discuss how the Underworld might actually be opened.
During an earlier visit to the Halls, Sylas had gathered detailed information about a particular structure: the stone archway housed in the Hall of Mysteries, and its relationship to the boundary between life and death. In the world of Harry Potter, the study of that boundary had never ceased.
The Death Chamber in the Department of Mysteries contained a tall stone archway, ancient beyond reckoning, which wizards believed to be a passage between the living world and whatever lay beyond. Those who passed through it did not return. The archway predated the Ministry of Magic and even the Department of Mysteries itself.
It had been discovered by ancient wizards studying death, who used it as the foundation around which they built their research, gradually extending their inquiries into time, fate, thought, and the mind, until that body of knowledge became the Department of Mysteries, and the Department became the cornerstone of the Ministry of Magic.
Based on what he had gathered, Sylas had already begun forming ideas and had drawn considerable inspiration from it. He and Mandos discussed the matter at length and arrived at a shared direction: they would create a spatial domain capable of receiving and housing all souls, and use a stone archway as the gateway through which the dead would pass into the Underworld.
Creating such a realm was no simple undertaking.
Mandos and Sylas invited Irmo, the Lord of Dreams and Visions, to join them. Mandos and Irmo were brothers, one holding dominion over death and the other over dreams, and together they were known as the Fëanturi, meaning the Masters of Spirits.
The three of them descended to the dark abyss beneath Arda, which they had chosen as the site where the Underworld would take root.
Mandos stood in the darkness and began to sing.
His voice became power, shaping a realm of death within the endless dark, expanding it outward, pressing back the surrounding void and carving space from nothing.
Irmo joined his voice to his brother's, and where Mandos's song gave the realm substance and boundary, Irmo's transformed it into something half-dreaming, neither fully real nor fully absent, existing apart from the physical world like a vision that cannot quite be touched.
Sylas did not stand idle. He poured his own power into the growing realm, threading time through it in a way that made it stagnant and still. Within the Underworld, time would not pass as it did elsewhere. The dead would dwell beyond its reach.
Others came as well.
Vairë, wife of Mandos, bound the threads of fate to the new realm. From that moment, when a lifeline was cut, the soul it belonged to would be drawn toward the Underworld as naturally as water finding its level.
Estë, the gentle wife of Irmo, added her own blessing to the realm, granting the souls who entered it the gift of eternal rest, deep and healing, free from the weight of pain they had carried in life.
Ulmo, who rarely confined himself to Valinor and spent most of his existence moving through the waters of the world, arrived unexpectedly and set to work, raising a vast river that wound its way through the Underworld and encircled it. Others among the Valar came to witness or lend their aid.
Aulë, the great craftsman, brought his power to bear on the realm's construction and shaped a boat that could not sink, built to travel the River of the Underworld against its current. Varda hung a crescent moon above the Underworld, cold and ominous, to give that dark place its own pale light.
Nienna wept, as she so often did, and her tears fell and became a river of forgetting. Any soul that drank from those waters would lose all memory of what it had been, freed at last from the burden of everything it had carried.
Yavanna tended the soil of the Underworld and coaxed pomegranate trees to grow there. The dead who ate of their fruit would take on a presence in the Underworld as solid and real as the living, no longer half-formed shadows drifting without weight or substance.
Vána caused red flowers to bloom in vivid abundance across the Underworld's landscape, so that the dead might find peace among their color and fragrance. Oromë provided a great hound to stand as guardian at the Underworld's threshold.
Through their combined effort, a complete Underworld came into being.
Sylas then took stone drawn from the Underworld itself and constructed a great stone archway in Arda, raising it as the gateway between the living world and the realm of the dead.
The archway carried a powerful pull on all unhoused spirits, drawing the souls of Arda through it and into the Underworld as though by instinct.
Mandos was deeply pleased with what they had built. He resolved to raise a palace of his own within a corner of the Underworld, an outer estate of Valinor, as he thought of it.
He even began making plans to transfer the souls of the Elves, Dwarves, and Men currently dwelling in the Halls of Mandos into the Underworld, where they would have the freedom to move through a realm far larger than any hall could ever be.
But while the attention of the Valar remained fixed on the Underworld and all it promised, a shadow moved quietly toward Valinor.
A dark figure, disguised as the spirit of a dead mortal, slipped unnoticed into the Halls of Mandos and began making its way in silence toward the Gate of Sorrow.