They were both very small the first time they heard about hobbits. Fili, of course, saw it as an opportunity for mischief. So when his little brother asked him, face alight with curiosity, what a hobbit was, there was absolutely no hesitation.
"Kili, shush!" he hissed conspiratorially, drawing Kili closer to his side. "You don't want mother to hear us talking about hobbits."
Kili lowered his voice obligingly, eyes widening. "Why must we not let mother hear us? Is there something wrong with hobbits?"
Fili clapped his hand over his brother's mouth, looking around the kitchen furtively, as if searching for danger. Mother and Thorin had moved into the other room, the conversation long since moved on from the brief mention of a 'hobbit-sized sword'. They seemed to have forgotten that it was long past the children's bedtime. "Shush!" Fili hissed again.
"What is it!" Kili demanded of him, pushing his hand away. "Fili, tell me what a hobbit is!"
"No, I shan't," said Fili. "I would get in terrible trouble."
"Trouble for what?" Kili's voice grew shrill at his older brother's lack of response. "Fili! Tell me right now or I'll get Mummy!"
Fili contorted his face into an expression of terror, secretly pleased that his plan was working so well. "No! Kili, you mustn't! She'll get angry at me for telling you about…the dire-hobbits." He continued in a whisper as Kili's eyes grew round as saucers. "She warned me never to talk to you about them, on account of you getting scared."
"I'm not scared," Kili insisted, tugging on his sleeve. "I promise I won't have nightmares, Fili. Please tell me."
Fili regarded him shrewdly, letting the younger dwarf fret for a few moments. "Alright," he said finally, grabbing Kili's hand and pulling him down the hall. "But don't say I didn't warn you."
They built a fort out of pillows and blankets on Fili's narrow bed, and huddled underneath a sheet with a candle and Kili's tattered teddy bear. There, as the wind howled outside and rattled the shutters against the windows, Fili began to weave his tale, drawing on all the scary stories he'd ever heard from Dwalin and the other older dwarves that sometimes visited. He spoke of a fiendish beast, a dire-hobbit, smaller even than they were, but with claws like razors and teeth that could rip a grown human to shreds in an instant. He spoke of its haunting wail that echoed through the moors in the middle of the night. He spoke, in the quietest of whispers, of its taste for little dwarflings, of the rare occasions it found its way up to the mountains and preyed upon the unwary children there, and of the way these children were never seen again.
As Fili spoke Kili's eyes got wider and wider, and he clutched his teddy bear ever closer to his chest, till Fili was sure the ragged toy was squashed flat. There was not a trace of disbelief on his little brother's face. Perhaps, thought Fili, I have taken this too far.
Then the bedroom door slammed open, and Kili let out a bloodcurdling scream, and threw himself forward into his brother's arms. Pillows and sheets went flying everywhere as they both toppled from the bed. Thank Aulë the candle was snuffed out in the process.
"And what, exactly, is going on here?"
Fili could not answer his mother for a good couple of minutes. His arms were full of Kili, who had curled up in his lap and was sobbing into his shirt-front, shivering with fright, and he was trying desperately to calm him.
"Shhh, Kili, I was just joking, I promise. There aren't any dire-hobbits, I made it all up. Look, it's just Mummy! It's just Mummy come to check up on us! Kili, I promise I was only joking. Don't cry, Kili, please don't be afraid. I was just joking, and I promise I'd protect you, even if I weren't. Shhh, don't cry, little brother. I won't let anything hurt you."
Dís stood in the doorway with her hands on her hips, watching as her eldest managed to stop his little brother's tears, with only his smile and his touch and the earnest promises of an older sibling. What treasures I have, she thought to herself, greater than any I once had in Erebor. But her expression remained unimpressed, and she tapped her foot expectantly, because she had to have some semblance of order in her house.
Fili looked up at her over his brother's head. Guilt and regret were written clearly across his face. "I lied to Kili," he said, ashamed. "I told him a scary story about dire-hobbits, and said they would come and eat dwarven children in the middle of the night."
"Dire-hobbits, hm?" asked Dís, with her brows raised. "Where, pray tell, did you draw that one from?"
"I made it up," Fili mumbled. He drew his fingers in lazy circles around his little brother's back, the way that Dís had done to him when he'd been small and afraid of the rats in the ceiling.
"Well," she said with a sigh, "you'd make a right fine storyteller, at least."
Then the floorboards creaked behind her, and Thorin was at her side, looking down at her two boys huddled on the ground. "You've got this sorted out, then?"
"Thorin Oakenshield, I know how to care for my own children without you sticking your long nose into the business."
The heir to the Lonely Mountain cleared his throat and folded his arms, more offended, Dís thought, by the comment about his nose than her tone of voice. "I heard something about dire-hobbits," he said gruffly.
"No such thing."
Kili sniffled and shifted in his brother's lap to look up at his uncle. He had to crane his neck a fair way back; Thorin seemed to loom to the ceiling, taking up the whole of the doorway behind Dís.
"Are you sure they're not real?" he asked hopefully, wiping a sleeve across his eyes.
Always so eloquent, Dís thought dryly.
But it seemed to do the trick. Kili climbed out of Fili's lap and up into his brother's bed, leaving it unspoken that he was going to sleep here for the night. Fili lay down beside him. He was still the picture of absolute remorse, and he hugged his little brother tightly to him with one arm, not minding that Kili took up most of the bed.
As Dís and Thorin headed back to the kitchen, closing the bedroom door behind them, they could hear the brothers still talking quietly.
"You promise you'll protect me?" Kili asked with a yawn.
"Always," Fili replied firmly. "I'll not let anything hurt you, not ever, Kili. I swear it."
And when Kili cried out in the night, his sleep haunted by dreams of dire-hobbits, his big brother was there to chase them away.