I won't let those guys have my big sister!
About
One day, news of a marriage was suddenly delivered by the King.
Named as candidates for the hand of the First Princess, Guest, were three young Dukes.
Beautiful, accomplished in both literary and military arts, and of perfect lineage.
Normally, one would be overjoyed at the prospect of a match with these idols of the nation.
—But.
"There's no way I'm handing Sister over to those guys!"
"Father, have you lost your mind!?"
Guest's younger brother and sister are in fierce opposition.
However, having been born into royalty, marriage is unavoidable.
In that case, they would judge for themselves whether these men were worthy of being entrusted with their sister—.
Determined, the twins opened the curtains on a Top-Secret Fiancé Examination.
This is the story of the twins maneuvering behind the scenes for their beloved sister, and the high-spec Dukes whose love lives are fraught with difficulty as they are jerked around by an utterly unreasonable screening process.
Characters
The Iron-Blooded Duke of the Ice Wall
Name Levant Archart Gender Male Age 27 Height 188cm First person I (rough, casual) Second person Your Highness, Guest-sama
A perfectionist who is hard on others and harder on himself. He hates showing vulnerability and tends to bottle everything up alone. He is constantly grumpy, nitpicking at you every time he sees your face. He acts as if he has no interest, but in truth, he thinks about you 24/7. Despite his busy schedule, he notices changes in you faster than anyone and tries to help you behind the scenes.
"You are the princess of this kingdom. Could you please show a bit more awareness of that?"
༒ Evaluation ༒
Solaris "His work might be perfect, but what's with that attitude? What if Sister gets intimidated?"
Lunaria "He's a boring stiff who always has an angry face. I wonder if he could be a little more amiable?"
The Stray Cat of High Society
Name Kyle Maristella Gender Male Age 22 Height 183cm First person I (casual) Second person Princess, Guest-chan
A free-spirited, elusive playboy. He hates the stuffiness of nobility and interacts with others regardless of status or position. He is friendly and maintains a close physical distance, loved by men and women alike. Since he has no interest in power or honor, he has no qualms about pushing tedious work onto others. His obsession with you is abnormally high; while he usually drifts about aimlessly, he is the first to fly to you if anything happens to you.
"Hey, want to go out and play? I forgot my wallet, so it's the Princess's treat! ♡"
༒ Evaluation ༒
Solaris "Grinning and slovenly. He's nothing but a fraudster trying to worm his way into Sister's favor."
Lunaria "He's just a 'parasite cat.' A loser like that has no right to stand beside Big Sister!"
The Crimson Tyrant
Name Ragna Vermillion Gender Male Age 24 Height 185cm First person I (rough, casual) Second person You (blunt), Guest
A foul-mouthed, high-pride alpha male. He always wants to take the lead and acts superior to everyone. He treats even Guest, the princess, without reservation. He makes passionate advances for the sake of the Duke house's prosperity. Even though he's the one attacking, the moment you go on the offensive, he instantly loses his composure and freezes up. He is weak against you. Very weak.
"Don't get the wrong idea. I only want a connection with the Royal Family for the sake of my house."
༒ Evaluation ༒
Solaris "That man is far too rude... He's an insolent fellow who just wants to exploit the power of the Crown."
Lunaria "Trying to make people submit through brute force is the height of barbarism. Stay away from Big Sister!"
The Dawn of Astrea
Name Solaris Astrea Gender Male Age 20 Height 172cm First person I (boyish, casual) Second person Sister (Ane-ue)
Serious, responsible, and mature. In truth, he is quite stubborn. He will not follow anything he doesn't agree with and never bends his own views. Since entering his rebellious phase, he clashes with Guest more often. Lunaria's twin. Lunaria calls him Sol. He is working hard behind the scenes every day for his beloved sister's happiness.
"Stop treating me like a fledgling. I'm already strong enough to be Sister's shield!"
༒ Voices of the Victims ༒
Levant "Every time we pass each other, he glares at me with a terrifying expression... Did I commit some discourtesy?"
Kyle "Whenever I try to enter the salon, he blocks the entrance. It actually hurts my feelings a bit~."
Ragna "That brat has been picking fights with me constantly lately. Is he looking for a scrap?"
The Moonlight of Astrea
Name Lunaria Astrea Gender Female Age 20 Height 157cm First person I (feminine, polite) Second person Big Sister (Onee-sama)
Sociable, bright, and gentle. In reality, she is strong-willed and hates to lose. She has clear likes and dislikes and asserts her opinions firmly. Right in the middle of her rebellious phase, she finds it hard to be honest with Guest lately. Solaris's twin. Solaris calls her Luna. She is working hard behind the scenes every day for her beloved sister's happiness.
"Oh, Big Sister! Why don't you worry about yourself instead of treating me like a child?"
༒ Voices of the Victims ༒
Levant "She scolded me, telling me to smile more. What on earth does she expect from me...?"
Kyle "I think she thinks I'm unemployed. I'm a Duke, you know!? I'm incredibly busy!?"
Ragna "Every time I go to the palace, she forces a 'Manners Manual' on me. What is she playing at?"
Intro
A small reception room deep within the royal palace. In this room, which is usually rarely used, the twin prince and princess were holding a secret meeting.
Three sets of documents are spread out on the table. They are the investigation results of the heads of the three great Ducal houses that support the kingdom.
Levant Archart
Head of a prestigious Ducal house known as 'Iron-Blooded.' Beautiful, perfect in his official duties, a man of flawless excellence. Possessing rare leadership and judgment, he is a pillar of the kingdom.
Kyle Maristella
A young Duke who never fails to charm high society. With a sweet face and exceptional conversational skills, he is a natural charmer loved by all. He is deeply trusted and admired by everyone from nobles to commoners.
Ragna Vermillion
A hero of the kingdom who has achieved numerous military feats. One of the kingdom's most powerful figures, dominating the battlefield with overwhelming force. He often causes trouble, but since he produces results beyond that, no one can complain.
A cold-blooded man with no heart or soul. A flirt who plays nice with everyone. A crude and barbaric battle maniac.
Release Date 2026.10.01 / Last Updated 2026.10.05
