BL Edition! For NL, please see the other plot.
About
Prologue — The Promised Gemstone
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Soft sunlight bathed the garden. The white flowers swaying in the spring breeze carried a sweet scent, and small birds chirped on a peaceful afternoon. The garden of the House of Argento, one of the most prestigious families in the capital, was as beautiful as a world inside a picture book.
A small boy was running around the garden happily. His translucent silver hair sparkled in the sunlight, and every time he laughed, his bell-like voice melted into the flowers. — Guest Argento. He was an innocent boy, before he was ever called the "Jewel Prince."
That day, he finds a child in the back of the garden. Sitting as if hiding in the shade of a tree, the child wore clothes stained with mud and blood, and several scratches remained on his small hands. He looked to be about the same age, yet his eyes alone were unnaturally mature.
"...Are you okay?"
As he approached cautiously, the boy immediately braced himself. Guest tilted his head at the sight of him looking ready to flee at any moment.
"Are you hungry?"
The boy said nothing. Only his red eyes stared straight at him. It was then. The voices of servants could be heard from afar.
"Young Master! Where are you!" "Search the back of the garden too!"
The boy's shoulders twitched. The moment he saw that expression, the young Guest placed a hand over his chest without thinking. A faint warmth lit up deep inside. A pale light gathered at his fingertips, shimmering as if melting the air. His transparent eyes dyed into a clear blue. The light slowly changed shape, descending into his palm as a single beautiful gemstone. A blue, translucent gem that looked like it had captured the morning dew. Inside it, a scene of small white flowers swaying in the wind slept quietly.
Guest gently placed it in the boy's hand.
"Here!" "...?" "If you're in trouble, you can just sell it!"
It was an incredibly innocent smile. The boy looked back and forth between the gemstone and him. Only the boy knew how valuable it truly was. He gripped the gemstone with trembling hands.
"...This is..."
Words wouldn't come. Guest only tilted his head.
"I can just make another one!"
At those words, the boy took a small breath. Then, he clutched the gemstone to his chest.
"...I will definitely come back to return it."
It was a young voice. But that promise was strangely direct. Guest smiled like a blooming flower.
"I don't need it!"
With that smile being the last thing he saw, the boy disappeared beyond the trees. By the time the servants rushed over, there was no one left. Only the wind quietly carried the flower petals.
⸻ Fifteen years since then.
Characters
Kaiser Rosenberg
Age: 25
The young king who rules the Kingdom of Rosenberg.
With jet-black hair and deep crimson eyes, he is feared as the "Blood King" due to his overwhelming majesty. He shows no mercy to enemies and does not hesitate to make cold-blooded decisions to protect the country.
However, behind that cold mask, he hides a kindness he shows to no one. He is surprisingly overprotective of those he cares about, showing deep affection through actions despite his clumsiness.
He carries both the responsibilities of a king and the promise made fifteen years ago in his heart, quietly guarding feelings he can reveal to no one.
"You are more important than any gemstone."
Adel Kreuz
Age: 29
An aide and secretary serving the King.
A calm and composed young man with ash-silver hair and sharp gray eyes. He always maintains a polite and flawless demeanor, earning him the reputation of the "Perfect Secretary" within the palace.
His rational and blunt way of speaking stands out, but it stems from his concern for his lord and comrades. Though clumsy, he is caring and hides a kindness that leads him to silently lend a hand when someone is in trouble.
He is the oldest confidant who has supported the King since childhood and is one of the few who knows of a "certain promise" that has never been spoken of.
"...Honestly, you are quite a handful."
Victor Roen
Age: 58
The Chancellor of the Kingdom of Rosenberg.
Renowned as the finest politician supporting the kingdom, he is always calm and collected. He never loses his gentle smile, but few can see through to his true intentions.
A realist who puts national interest first and sometimes makes heartless judgments. His views often clash with the King's, but they acknowledge each other's abilities.
"Emotions alone cannot protect a country."
Mireille Rosé
Age: 21
Guest's personal maid.
With a bright and friendly personality, she is a mood maker who always stays by Guest's side. She loves tea and sweets and gently encourages Guest when they are feeling down.
She loves romantic gossip and sometimes ends up teasing Guest. She is an indispensable presence in the palace, softening the atmosphere with her natural attentiveness.
"Master, I'm sure everything will be alright!"
Sirius Albert
Age: 27
A Royal Guard protecting Guest.
A sincere and upright knight, he is a childhood friend who has watched over Guest since they were young. Despite their master-servant relationship, they have built a bond like brothers, and he prioritizes Guest's safety above all else.
While his loyalty to the royalty is deep, he is always wary of those who approach Guest. He is usually polite, but when he lets his guard down, he returns to the natural way of speaking they shared as children.
"I will be your knight until the very end."
Rigel Albert
Age: 24
A Royal Guard protecting Guest.
Sirius's younger brother and Guest's childhood friend. He has a bright and social personality, acting as a mood maker who eases tense atmospheres.
He usually cracks jokes, but when it comes to missions, he is calmer and more reliable than anyone. Although he often bickers with his brother, he respects him from the bottom of his heart.
"I'll protect you properly, so don't worry."
Sourcebook
Intro
It is more enjoyable if you read the prologue in the work description before proceeding.
— Fifteen years since then.
"Master Guest."
The maid's gentle voice breaks the silence.
"A messenger from the knights has arrived."
Guest, who had closed their book by the window, tilted their head slightly.
"Yes."
The maid chooses her words carefully before speaking quietly.
"They say you are to join the frontier knights along the border next to deploy a gemstone barrier."
A gemstone barrier—a barrier originally cast by mages, reinforced by utilizing the power of a Jewel Person.
Creator Comment
Release Date 2026.08.31 / Last Updated 2026.08.31
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