Mahal, the great father of all Dwarves, brought Durin into the world alone, no Dwarrowdam laid by his side.
The other Fathers of Dwarves he bound by the same biology as the Elves and Men, but to the children of Durin he gave his most precious gift. Mahal taught Durin how to carve his children out of stone, the same way that Mahal had created him.
Never once in all his long years had Thorin felt the pull to craft a child. First he was too young, then nothing but the stone of Erebor would do, then he could barely breathe for missing Bilbo.
It was Bifur who brought him the narrow block of pale green marble.
The stone was smaller than most Dwarves chose, but it was veined with ripples of golden-white, the color of Bilbo’s hair in the midday sun. Bifur laid the block gently down on Thorin’s personal forge and grunted that you didn’t need much to carve a half-Hobbit child.
Every night for months Thorin sat beside the stone, running his hands along the surface to get a sense of how his child was curled up inside, what shape the boy would take when Thorin chipped back the layers. He sang to his son the Eddur of his ancestors, and told him of his beautiful, gentle father. About a peaceful people in a far green country who bred the most fearless person Thorin had ever met. About how his father had faced down a dragon and won.
Thorin’s nephews stumbled across his preparatory sketches, and in between hugs they insisted that their cousin have Dwarven feet (Erebor winters were too cold for anything else). They let him keep the tangled curls and snub nose, but his hair had to be black like Thorin’s and his eyes the Durin blue. (“Bilbo thinks his eyes are plain, Uncle. He wouldn’t wish the same on his son.”)
Three months to the day after Bifur brought him the marble, Thorin began to chalk the outline. He remembered the way Bilbo liked to sleep, sprawled on his stomach, legs akimbo, and shaped their son just the same. He chipped away the empty space around his child, the stone clinging to his arms, weighing down his still-hairy feet. Then he took the chisel to define the plump curve of his cheek, to give him ten tiny fingers and ten tiny toes.
It was the first blush of spring when Thorin gathered the Company to stand outside his workroom door and wait. They huddled in a pile of hugs and held hands, whispering quiet prayers that the child might live. Soon they fell to silence, then one by one began to sing the Song of the Lonely Mountain. (It had convinced the boy’s father to come with them, so it might do the same for his son.)
Alone in the room, Thorin carved into his son’s wrist the same marks all the Dwarves of Durin bore, the secret Mahal had taught their first father to bring them breath. Into the tender stone Thorin etched the secret rune that spoke his own name, and beneath, two bound B’s in the delicate, Elven cursive Bilbo preferred. Across the pad of the child’s palm he tapped an arc of seven stars to call on the gift of the house of Durin. Then he pressed a kiss to the place where his son’s pulse might be, the same spot as Bilbo’s initials. With a ragged breath, Thorin, son of Thráin, son of Thrór, King Under the Mountain, heartbroken lover, and terrified father, begged the oldest, most sacred prayer of Dwarrow kind.
“Eru Illúvatar, father and creator of us all. I desire this thing other than I am, to love and to teach him, so that he too might perceive the beauty of Eä, which thou hast caused to be. May Eru bless my work and amend it.”
Thorin trailed off into silence, and could not bring himself to open his eyes. These last months and been ones of almost contentment, and in this moment he careened near hope. If he stayed as he was, he could hold to this moment forever, but if he opened his eyes, then he would have to face the truth. The child beneath him had not cried, had not breathed, had not twitched.
With a shuddering sob, Thorin climbed atop the workbench and curled himself around the still, stone statue of his son. This child was meant to have rosy cheeks and a mischievous smile, but he would never know the halls of the mountain, never know the laugher of his cousins, never know about the gardens Thorin had tiered outside so that his son would have his father’s earth to grow in.
What possessed him to believe he would have the strength to bring a child into the world? He had betrayed his lover for a lump of rock, and so rock his son would remain since he valued it even above his One. It was nothing more than he deserved.
And yet, still he pressed his lips to the child’s pointed ear and murmured, “Thain would’ve been your name. For both his clan and mine. He told me a story once that his mother would’ve been Thain of the whole Shire if Tooks were a bit better about listening to their daughters.” Thorin ran a shaking hand over the soft curls atop his son’s head. “I know so little about your father’s people, but I would’ve told you everything, would’ve sent an emissary to his Shire that you might know all. Might someday even see his beloved Bag End.” Thorin’s voice cracked at the thought.
A small, soft palm cradled Thorin’s cheek. “Don’t cry, Adad.”
Hesitant, Thorin opened his eyes to find his own blue-eyed gaze staring back at him from a face soft like Bilbo’s. The boy took a solid axe-grip on Thorin’s braid and dragged him down until their foreheads bumped. “You and I, Adad, we’ll be alright.”