Little Devil Princess My Sisters Are Seriously Trying to Marry Me When They Grow Up

In the morning, a young boy stepped out alone while the castle still lay in quiet slumber.

The castle gates were firmly shut, and the gatekeeper, who had been on watch all night, was nodding off as if rowing a boat in his sleep.

Evading their watchful eyes had become an easy task for the boy.

He effortlessly left the castle and headed towards the forest.

The forest, dense with trees, was slightly dark and emitted a somewhat eerie atmosphere.

Undeterred, the boy ventured deeper into the woods, eventually emerging into a clearing.

A vast space with nothing particularly eye-catching.

However, this bland, spacious place was a precious and comforting spot for the boy.

“Alright, let’s do this today as well…”

After leaving the castle, he carefully drew the sword he had been carrying with great care. Its blade was about two shaku (approximately 66 cm), quite large for his small stature.

Even what was a short sword for others was like a long sword to him.

Unconcerned, he swung the disproportionately large sword vigorously.

Each swing through the air made a ‘whoosh’ as if the atmosphere was groaning under its weight.

“I’ve swung swords in my previous life, too.”

“So, it won’t hurt to keep it up in this life too.”

“Huh? So that’s where you’ve been sneaking off early in the morning.”

Startled, the boy cautiously looked behind him.

How had he been discovered? The boy had no clue.

He stared inquisitively at the demon who had appeared, leaning against a large tree.

A small sigh escaped from Amon’s beak.

“Even though we have a contract, it’s bothersome when you wander out of sight. Don’t forget that you’re still a ten-year-old child.”

“I know, I know…”

The boy, who was once a baby, had now turned ten.

At the midpoint of the contract, his life so far had been splendid.

Time spent with his new family and friends, transcending the barrier between humans and demons, brought richness and peace to his heart. His days were noisy yet enjoyable to such an extent that he never lost his smile. Gradually, his guilt and fear of pretending to be the Demon King faded away in these days.

“No one ever questions me about it, huh?” he thought earnestly.

There was nothing in the boy that suggested he was the son of Astaroth.

This was to be expected given his human origin, yet no one ever mentioned it.

“But it’s already been ten years, huh…”

The flow of time is truly cruel. The boy confronted this reality once again.

“Your dedication to training is commendable, but I don’t think highly of you wandering around alone, nor do I recommend it,” said Amon, looking exasperated. The boy’s face puckered slightly in response.

“No, but Amon-san, sometimes I just need some time alone.”

“I understand your feelings, but you’ll get caught sooner or later. And if you are caught, there’s a good chance you’ll lose your freedom.”

The boy blinked in confusion, not comprehending Amon’s words.

“Why?” The boy’s question was a natural reaction.

“Think about it. You’re a minor and alone in a place far from the castle. If you were to get injured here, they would surely take measures to ensure it never happens again. Then, you might be confined to the castle until you come of age.”

“That would be a real problem!”

“Then you’d better head back quickly. You can still make it.”

“Sigh… I guess I have no choice.”

“Also, remember that after breakfast, we have training together. I assume you know that—”

“I know, I know… Don’t stuff my stomach too much, right?”

“Good, as long as you understand. Now hurry up, boy.”

Urged by Amon, the boy had no choice but to comply reluctantly.

The remnants of his unfinished training still smoldered in his soul.

“It’s the most fun from that point on,” he lamented; however, when weighing freedom against it, he knew which was the right choice.

He wasn’t foolish enough not to know the

answer. He realized that the only way was to grow up. This, he told himself firmly.

“Good morning, Ryushi-oniisama!”

“Ah, yeah, good morning. I keep telling you to knock before entering, okay?”

The young boy, now addressed as Ryushi, appeared amused yet exasperated as the little girl barged into the room without knocking.

Ryushi was the new name given to the boy.

“But I woke up early today to wake you up, Ryushi-oniisama! Why are you always awake before me?”

Arissa, the girl with the short navy-blue bob, seemed quite upset.

She puffed her cheeks in protest, a reaction fitting for her appearance.

Though she intended to appear angry to Ryushi, she still looked like a cute little sister.

Of course, saying that aloud would surely upset her more than anything, so Ryushi wisely chose to remain silent.

“Ryushi onii-sama!” said Arissa, showing her anger.

Ryushi smiled gently in response to his sister’s eagerness.

“I’m sorry; I know you came to wake me up. Just by chance, today I happened to wake up early. Can I count on you next time?”

“Of course, it’s a promise!” Arissa replied, but then suddenly exclaimed, “Oh! That’s right!”

“What’s up?”

“From today onwards, I’ll stay in your room every night to wake you up!”

Ryushi couldn’t help but smile wryly at her proposal, which she seemed to think was brilliant.

That was not allowed. Ryushi gently reprimanded Arissa, whose round eyes sparkled with excitement.

“That’s a great idea, Arissa, but I can’t recommend it.”

“Why not? It’s such a wonderful idea!”

“Well, it’s just that it’s a bit dangerous.”

The growth rate of demons is much faster than that of humans. By their teens, their bodies are nearly adult-like.

Arissa, still in her teens but a demon, was too much of a mental stimulus for Ryushi, who had seen much of the world. Arissa was his sister, and a brother who laid hands on his sister was nothing but the worst. Ryushi firmly vowed never to make such a mistake.

“But she’s going to be beautiful in the future.”

“That’s something I, as a brother, definitely want to see.”

“So, no staying over. When something becomes too common, be it humans or demons, they take it for granted. The reason I appreciate Arissa coming to my room is precisely because it’s not every day.”

Ryushi’s rapid explanation left Arissa confused, causing her to tilt her head in bewilderment.

“I’m happy when Arissa comes to my room.”

“I see! Then I’ll come wake you up as usual from tomorrow!”

“Don’t forget to knock first.”

“Of course, I’ll remember to knock next time.”

“Good—then shall we go for breakfast?”

“Yes, Ryushi-oniisama! After you.”

“Hm?”

Ryushi was puzzled as Arissa held out her hands.

He looked at her quizzically, wondering if she was asking for something.

“Please!”

“But what do you mean by ‘please’?”

Ryushi was completely at a loss to understand his sister’s thoughts.

Impatient, Arissa explained.

“I mean, please undress so I can help you change!”

“Ah, I see.”

Ryushi finally understood.

“If you had just said so from the start…” he thought, clapping his hands in realization.

“Sorry, Arissa. I’m not wearing pajamas anymore. I’ve already changed, so no need to worry.”

“What a terrible thing to say!”

Arissa drooped in disappointment, appearing as if her world had ended. Ryushi was surprised by her reaction but also found it somewhat amusing.

“It’s not that big of a deal.”

“What do you mean? Do you understand how Arissa feels, having the joy of witnessing Ryushi-oniisama’s change taken away?”

Ryushi sighed heavily, pondering where he had gone wrong in educating his sister.

As a brother, he was worried about her future, which seemed  to be heading in a rather twisted direction.

“I need to find her a suitable marriage partner. That is my duty as a brother.”

Quietly, Ryushi looked down at his clenched fist.