Raising a child was not a particularly difficult task.
At least, raising Rinko was not particularly difficult.
But Muzan believed that every craft had its specialist.
If it was only for passing the time, then it was easy.
If the goal was to systematically and thoroughly make a child understand what it meant to be a demon, then he was not the right person for that job. Or rather, he had no intention of trying.
Fortunately, among the demons under his control, there happened to be someone who already knew Rinko and was very suitable for looking after a child.
Rinko was brought by Muzan to meet someone.
More precisely, to meet another demon.
When Rinko stepped out from behind Muzan, he did not miss the flicker of surprise that flashed through Tamayo's eyes. The tremor in her pupils betrayed the ripple in her emotions.
"You seem surprised."
Tamayo lowered her head and let her gaze drop, avoiding his eyes as she quietly explained.
"A child this young becoming a demon is extremely rare. And his body has always been very weak."
Muzan did not fully believe her explanation, but he did not care what Tamayo was really thinking. All he needed was someone who could teach Rinko the basic truths a demon ought to know. Someone who could personally take him out to see and experience the world. Tamayo was very well suited to this task. At the same time, she could help probe why Rinko had managed to withstand so much blood in such a short time and still successfully become a demon.
After leaving a few instructions, Muzan disappeared from the room, leaving only Tamayo and Rinko staring at one another.
"Hello, my name is Rinko. It is a pleasure to meet you. Please take care of me."
Those were the first words Rinko ever said to Tamayo.
Tamayo did not truly relax until Muzan had gone.
Only then did she finally have the chance to take a good look at the child she had once watched over.
Back then, he had not been called Rinko.
Back then, he had not been a demon.
He had only been a frail human child.
A fragile body could be nursed back to health, slowly, over time. Even if it never fully recovered, he should still have had the chance to one day run freely under the sun.
But all of that was only a fantasy now.
"You can call me Tamayo."
While Muzan had been speaking to her, Rinko had kept his head lowered, silent and still. Only when Muzan stopped talking did Rinko finally lift his face. Muzan treated him the way one might treat an obedient pet, stroking the boy's head while giving orders, never considering his thoughts, never giving him a chance to speak.
"All right. Tamayo-san."
Only after Muzan left did Rinko, like her, seem to regain some freedom of movement.
Poor child.
Muzan's instructions had been to teach Rinko everything a demon ought to know. It was a very broad assignment, with very vague limits. To Tamayo, it felt like an almost unreal experience.
She had lost her own child long ago, yet so many years after becoming a demon, she had somehow been given another.
A child she had to personally care for.
A child she had to gently guide.
A child who had become a demon.
Despite being a demon, Rinko did not even possess what was almost an instinct for their kind: the ability to kill and feed.
This, to Tamayo, was a good thing.
But for a demon, it was anything but normal.
Fortunately, Rinko was not repulsed by human flesh. He would drink human blood as well. It was just that each time he fed, the amount he consumed was very small, making Tamayo wonder if this was why his body remained so weak even after becoming a demon.
The cause was easier to guess than the conclusion.
Tamayo had once acted as the physician caring for Rinyo. At that time, she had already noticed that his body showed signs of long-term abuse. Years of torment had left both his mind and his flesh covered in wounds. Perhaps because the memory of being too weak to eat much as a human was so deeply carved into him, even after becoming a demon and losing his human memories, Rinko's stomach still rejected being stuffed full of anything.
Rinko ate very little and spent very little. He had his own way of living, like some frail, slow animal that survived on the absolute minimum amount of energy needed to keep breathing.
Tamayo did not know whether his gentle personality had shaped his habits, or whether these quiet, restrained habits had shaped his gentle personality.
She only knew that Rinko did not feel very much like a demon.
He was a small boy who had neither the energy a child his age should have nor the cruelty a demon his age usually did.
Compared to killing, hunting, and feeding, or any other demonic pursuit, Rinko much preferred to sit quietly indoors. Sometimes he read. Sometimes he practiced his characters. Sometimes he crouched at the door and played with stray cats that wandered past. Other times he stood beside her while she made medicine and wrote down her notes, asking if there was anything he could help with.
When there was nothing in their lodgings to pass the time with, Rinko would go out for a walk after getting permission. The length of time he was gone varied, but he rarely went very far. The constant was that by the time he came back, there was always something new in his hands.
A few pretty leaves.
A few fruits he was not sure were ripe.
Or a baby rabbit.
All of these would be placed in front of Tamayo.
"Tamayo-san is very kind. This is my gift in return."
That was the answer she received when she could not help asking about it.
The boy kneeling opposite her was serious and earnest. When Tamayo turned her surprised gaze on him, that face that almost never showed emotion softened with a warmth she had never seen before.
Even after becoming a demon, his nature was still gentle and kind. He did not delight in killing. He did not believe he was entitled to everything. He was always grateful for what he was given.
The more clearly Tamayo saw this, the more vicious and cruel Muzan seemed in her eyes.
A child like this should have had a future that would make people happy for him. He should have grown up slowly. He should have become someone others could rely on, someone whose name would make people smile when they mentioned it. He should have had his own family, helped many people, perhaps taken a wife, raised several children, and lived happily under the sun until the end of his days.
He should not have been doomed to walk only in darkness, to spend one day after another asleep in shadowy corners just to get through the sunlit hours, to be cursed and despised as a monster by everyone who discovered what he was.
Rinko stayed by Tamayo's side for many years.
To a demon, many years was not really so long.
Tamayo still looked young.
Rinko was still a child.
Aside from the fact that a growing boy required more frequent changes of residence to avoid notice, not much else changed.
For Tamayo, the days with Rinko went by faster and were kinder than those before. Perhaps because of that, Muzan had rarely sought her out in those years.
Which was why, when Muzan appeared in the dead of night, Rinko's memory of him was already blurred.
The boy stood in the open doorway for a while before finally remembering how to address their guest.
"That was very rude of me, Rinko."
"I am very sorry, Lord Muzan. It has been a long time. You look as vigorous as ever."
Rinko smoothly corrected himself and stepped aside to let Muzan in.
Tamayo cast a subtle glance at the demon who had come for no apparent reason, a nervous twinge rising in her chest.
Unlike Tamayo's unease, Rinko showed an unusual closeness toward Muzan. Even though they had not seen each other in many years and Rinko had almost forgotten him, once Muzan stepped into the house, the boy trailed after him like a little shadow.
Muzan questioned Tamayo about her recent progress in an offhand tone, casually flipping through the papers on her desk. Rinko followed along behind him, looking once more at bottles and jars he had already seen hundreds of times.
"How is Rinko's training coming along?"
The topic shifted quickly. The boy only lifted his head slightly when he heard his name.
"He has basically learned everything he needs. He should not have any trouble surviving."
Tamayo lowered her eyes, avoiding the gaze that turned toward her.
Muzan did not pay her much attention. He looked instead at Rinko.
"Then come with me, Rinko. I will take you to meet our new friend."
It did not sound like a good thing, whether from the deeper implications or on the surface. Tamayo was about to say something, but before she could speak, she heard Rinko's answer.
Firm. Immediate. Without hesitation.
"Yes."
"Tamayo, do you have something to say?"
This time, the oppressive weight of Muzan's stare fell squarely on her.
"No, Lord Muzan. Nothing. Rinko is already capable of acting together with you."
Other than that firm response, she did not dare let any other words escape.
Muzan walked past her, with Rinko following close behind.
"Tamayo-san, I will see you next time. I will remember to bring you a present. Please take care of your health."
Rinko's voice was very soft, but Muzan had surely heard it. He simply did not respond, as if he did not care.
Only when the front door closed and the house returned to its long-lost silence did Tamayo suddenly collapse. She sat down on the floor, her eyes fixed on the ground, and every thought in her head revolved around that boy.
She had wanted to keep Rinko.
That fragile child had no ability to protect himself. If he encountered a Demon Slayer, he would be in danger. His head would be struck from his shoulders with ease. There was no doubt about it.
Muzan did not truly love him.
That monster did not even understand what love was.
But just as she had once failed to keep her own child, she could not keep Rinko either.