Fire in the lower galleries, smoke in the tunnels. Poisonous gases and heat and explosions, collapsing homes and escape routes caving in. Cracking stone, screams, a metropolis darkening under the roars of a demon from the deep. The king does not need to see to know what is happening to Khazad-dûm. The miners and soldiers are blocking off the tunnels from the mithril mines into the populous heart of the great city, trying to seal the air locks to hold off the noxious fumes that are asphyxiating his people, trying to fight a monster made of flame and shadow. Durin’s people need time to flee to safety, and the universe has been overturned, for safety used to mean deep underground. His civilians, his few mothers and children, the most precious jewels of the Dwarves, need time to reach the uppermost levels and gather supplies to survive a possible exodus through hazardous lands. If the locks cannot hold, if the Balrog makes it from the deep mines into the wide thoroughfares, Khazad-dûm is doomed.

They need their king to lead them. Durin gives his son Náin a final set of instructions, the plans to divert the aqueducts and flood the lower levels in a deluge that shall hopefully defeat the demon of flame if all else fails. Minor versions of similar plans for smaller emergencies, gas leaks and caves-ins, orc invasions, have long been on file. For several hours Durin has conferred with his son over the strongest locations in the mountains to hold out for a final siege and concurred with Nain’s proposals on how to best adapt the emergency procedures. Nain’s face beneath the raised visor of his helm is pinched with worry, but Durin has faith in his son’s capabilities. Gruffly, he reassures his son a final time on the soundness of their plan, one Nain still clearly believes should be his father’s duty as king to lead. After initial arguments, when it became clear changing the courses of aqueducts would be easier than changing the will of his father, Nain has not disputed Durin’s intentions to join the soldiers in the lower galleries. His son knows an unbeatable fight when he faces it.

Durin dons his golden helm and face-mask and heads for the door. The guards open it to someone Durin expected to have long retreated with Nain’s wife and barely-adult son. Nain only nods briefly in respect to the new arrival. There is a flash of what might be guilt in his son’s eyes, for it is obvious Nain knows why this person is present in the Chamber of Mazarbul instead of safely guarded near the surface levels. A suspicious corner of Durin’s mind wonders if the search through the records of the city layouts has been orchestrated so this new arrival would have time to sneak back into the Seventh Level and confront Durin. Has Nain recruited the only person his son hopes could persuade Durin away from what they both know is a sacrificial last stand? He glares at his son instead of his guardsmen. The king is not surprised that his guards defer to this person, however much he might wish otherwise. No door in Khazad-dûm is barred to him. The arrival blocking the doorway is someone most precious to Durin and his people, someone who has been a heart-companion during the many repetitions of Durin’s life. The tallest person in the room, with the shortest beard, he kneels down before Durin arrayed in a coat of silver mithril. He is holding what Durin at first mistakes for a slender pole-arm. Durin frowns and commands, “You should be with the other lore-masters and master-craftsmen. You are too valuable to lose.”

Precious barely begins to describe the feelings the dwarves of Khazad-dûm feel for this one. The only non-dwarf in Khazad-dûm, the one to give the dwarves the first letters in which to preserve their history, he has rejected all names but those the dwarves have given him, and the name that Durin’s people call him is Preserver of History. The truly deathless one, the Preserver of History remembers Durin II, having lived with that king during the end of the First Age and into the Second. He is the one who would recognize when Durin returned to his people with each rebirth, proclaiming the news to eager mothers and lore-masters. Those sad grey eyes of his eternal faithful friend, the first Durin can remember meeting upon this earth, lock gazes with his king once more. Stubborn as any dwarf, his heart-friend.

“You should not be arrayed in armor,” Durin says more forcefully. “You are not a warrior.”

“You will not send me from your side,” Daeron answers. “I will not abandon my home or king to destruction.”

“You will!” Durin growls. “You will not survive against a Balrog, you fool elf!”

Some of the shocked gasps from others in the room might have been at the acknowledgement that Daeron, Durin’s Treasure and Preserver of History, was an elf. It was a tactfully ignored truth. They knew the lore-keeper had once held a similar exalted position among the elves. However Daeron has lived so long among the dwarves of Khazad-dûm, sharing in their familiar pains, delighting in their joys, attending loyally to their king, and hiding from his former people even during the time friendship with Eregion blossomed, that they forget it had not been Mahal’s hands that shaped him. Durin II had welcomed Daeron into his home, cloistered him deep within the heart of the mountain, and over time taught him the secrets of the dwarves. Each year Daeron’s wistfulness for long-gone forests and heartbreak for a long-dead unrequited desire had lessened under the admiration and affection from the people of Khazad-dûm and the closeness of their king. The dwarves understood such heartbreak and how to heal it. Daeron had been appreciated in his first underground home, highly respected by its rulers, but Durin knows the nostalgia Daeron feels nowadays lingers solely inside these halls, for these caverns above the Kheled-zâram. For centuries only Khuzdul has passed through the elf’s lips. His songs are lullabies to sing to dwarven children. The stars he praises are the reflections from the Mirrormere. The lore he gathers and shares comes from the wisdom found here in Mazarbul. Daeron’s skill as a craftsman of wood is equal to Narvi’s with stone, or any other of the great artists of Khazad-dûm. His patience and willingness to teach that skill is even more rare and valued. Nain’s son learned to carve wooden marvels, form his letters, and play the harp on the lap of his grandfather’s heart-friend. Durin does not wish Nain’s grandson to grow never knowing of Khazad-dûm’s most treasured secret.

The rest of the astonished cries come from how Daeron has not budged, staring like an unmoved cat in defiance to his king. Durin cannot push him aside, so he moves to divert around him as one does when tunneling and faced with stone too onerous to chip through. Daeron grasps his king’s hand and turns Durin to face him once more. Grey eyes impede him.

“I will go with you, to death this time, so be it! And here is my weapon, my king, to wield in service of you and our people. Song has defeated the enemy’s monsters before. If mine is still the greatest voice to ever grace this world, then its greatest use will be to sing enchantments to ensnare this demon in the depths, perhaps to lure it back to slumber for as long as my power holds. Enough time to buy our children a chance for safety.”

Durin weeps into his beard as Daeron reverently kisses the crown of the helm, then kneels even lower to pull Durin’s gauntleted hand to his lips and then to caress the side of his face. “We go together this time.” Daeron whispers.

(Edited to match AO3)