The Youngest Son of the Northern Grand Duke Decided to Divorce

### Chapter 1

The Grand Duke of the North wanted to raise a child capable of inheriting his title. Of course, the title was just a formality, and he needed to find a commander to govern the northern territories. A title alone couldn’t lead the northern army or stand against monsters and barbarians.

“……Collapsed again?”
“Yes. He overused his magic and collapsed,” answered Tina Radiant, the third daughter of the Radiant Grand Duke family. Her younger brother had already proven his abilities, but his frail health couldn’t withstand the flow of magic. Despite his efforts, he couldn’t overcome his natural limitations.

“I’ve told him repeatedly to take care of his body, but he never listens.”
“He probably doesn’t want to remain as he is. He must think he has to do something.”
“If he dies trying, who should we blame? Not all problems can be solved with effort.”
Jaior Radiant, the head of the Radiant family, sighed deeply. He had a hard time getting his youngest son, but who knew he would be so weak? He had been collapsing frequently since childhood, sometimes even coughing up blood. Nowadays, even walking slowly seemed like a miracle.

“I understand, but please try to understand Alter’s feelings a bit.”
“Understanding changes nothing. Your brother can’t do anything. He can’t even eat properly or exert himself. Should we just let him be?”
“Father, we can’t do nothing.”
“Alter must do nothing if he wants to stay alive!”
“……”
Tina hesitated before closing her mouth. She wanted to support Alter’s actions but couldn’t deny her father’s words. Her brother, Alter Radiant, struggled even to keep himself alive.

“He has a talent for magic, and I would support him if he wants to learn. But he shouldn’t. He could die any moment, and should he really be clinging to magic?”
“Our family can protect him now, but he will have to live on his own later. Shouldn’t he at least learn magic for……”
“That’s why we arranged a political marriage with the Ducal family. The capital is better than this place. The Duke’s family can use their connections to find medicine or priests. I’m trying to save your brother!”
Jaior raised his voice, clearly agitated. He kept Alter within the estate, excluding him from even basic training, hoping to keep his frail son alive. But he knew he couldn’t protect him forever and had to find a new solution.

“I understand your point, but I’m worried. His fiancée…… I mean……”
“Are you trying to say she has a bad personality?”
“I wouldn’t say she’s good. Even if we overlook her activities as a knight, she’s known to be hot-tempered and wild.”
Tina didn’t favor her brother’s fiancée. Though she was a Duke’s daughter, her behavior and character were questionable. She feared her brother would suffer if he married her.

“They knew what they were getting into. Each side has flaws, so they’re quietly accepting it.”
“In terms of rank, you’re above them, Father. I don’t think we lack authority or wealth.”
“The Illenat Duchy is a powerhouse in the capital, representing one of the factions and maintaining good relations with the royal family. In that sense, rank means nothing.”
“I wonder if they will treat him well. They might look down on him for being weak.”
“It’s a political marriage between a Grand Duke and a Duke. Being disrespectful will only harm them.”
Jaior had already grasped the conditions and mutual benefits. The Duke wanted to expand his influence beyond the capital, while he needed an ally among the capital’s nobility. Despite their children’s obvious shortcomings, there were no major complaints about the marriage.

“Still, I’m not sure if Alter can handle it. He will have to marry and live in an unfamiliar place.”
“Your brother understands. He may be weak, but he’s not foolish.”
“……When will you send him?”
“Soon. He might improve in a better environment.”
“I suppose I’ll be next then.”
Tina’s engagement to a Marquis’s son was already planned. Unlike her brother’s situation, it was purely a political marriage for the family’s benefit. She couldn’t complain much, as her fiancé was at least well-mannered and respectable.

“You both will live in the capital. It might be a bit troublesome, but…… Take care of your brother. Explain things well to your fiancé.”
“I intended to look after him anyway. I can’t just leave him to marry that kind of woman.”
Tina always looked out for her brother. Had he been healthy, he would have become a great mage, shaking the empire. But now, he had lost his confidence and became introverted, making minimal efforts to improve.

‘My poor brother. I hope you get better………’

***

Instinctively, Alter opened his eyes and saw a different scene. He had briefly used magic earlier, but his vision went dark, and he felt his body being twisted. ‘Did I faint from using such little magic?’

Alter Radiant, the youngest son of the Radiant family, realized his reality. Originally, the character Alter Radiant was supposed to die, and the protagonist would naturally break off the engagement. But Alter Radiant was still alive, and he was now in that body. ‘So, the original owner of this body is dead, and I’m replacing him?’

Understanding the situation, Alter tilted his head. In the original story, Alter Radiant was a minor character mentioned early on. His death would lead to changes in the protagonist’s life, setting the stage for the story. ‘The protagonist isn’t important right now.’

Struggling, Alter got up and clutched his left chest. His heartbeat was irregular, and his muscles were stiff. Even slight movements were challenging, making him acutely aware of his condition. ‘How can a body be this weak? What is this?’

His condition had worsened even before using magic. He could walk, but running made his legs tremble. The faintest cold made him shiver, and his skin felt frozen. How could he survive in such a body? ‘Is it the magic keeping me alive?’

He understood the principle without realizing it. Normally, a body relies on bones and muscles for action. But his body was too weak for bones and muscles to function properly, so vast magic power was compensating for it. ‘So, great talent can achieve this?’

Barely able to leave the bed, Alter stood up, feeling his whole body creak. He managed to stay upright, but just attempting magic had made him faint. ‘With this body, I can’t do anything. Breathing is all I can manage.’

Finally, he began to think about his future. Since he hadn’t died, the engagement with the protagonist wouldn’t be broken. So, if time passed, he would be forced to marry the protagonist. ‘I need to break off the engagement. How do I persuade them?’

After some thought, he made a simple plan. The Grand Duke wanted a political marriage for the family’s safety and benefit. He just needed to change the process. ‘Competing with talented people isn’t for me.’

***

Before dinner, Jaior met Alter. Alter was already in the dining room, joined by his elder brother and sister. Given the recent incident, Jaior had to warn Alter.

“I’ve told you many times, don’t use magic. You’re only hastening your demise.”
“Yes, I apologize for worrying you.” Alter replied politely, glancing around. He had already heard countless scoldings from his family. It seemed the Radiant family was deeply concerned about him.

“……I have something to say. May I speak with you privately?”
“Speak freely.”
“I want to break off the engagement.”
“Mm?”
His brother and sister reacted immediately, but Jaior remained silent. Alter might be weak, but his judgment was sound. He must have a reason for mentioning the engagement.

“……Breaking it off now won’t benefit us. The Duke’s family offers convenience. You know that.”
“I don’t intend to avoid marriage. But to change the partner, we must break this engagement first.”
“Do you want to marry another noble?”
“Yes. I think it would be better.”

Political marriages among nobles had long been a tradition in the empire. They also avoided marrying within the same bloodline, constantly seeking new noble families. Therefore, Alter had to marry a noble, but he could create a reason to avoid the protagonist. “Only the royal family is above the Duke. Do you have another reason?”

“Father, the royal family would be burdensome for you. There would be many concerns, and they could trouble us. While the Duke’s family is easier in some ways, they are still difficult.”
“Your point isn’t entirely wrong. But the benefits are worth it. A powerful family would benefit us. That’s why I chose the Duke’s family, despite the difficulties.”

Jaior listened to Alter’s serious reasoning. Though he could have used authority and rank, he preferred understanding the reason behind the desire to break the engagement and correcting any mistakes. “Duke Illelnat is ambitious, forming factions and currying favor with the royal family. If we form an alliance, they might manipulate you.”

“…….”
Jaior quietly observed Alter. This had been a concern since considering the political marriage. In a network of alliances, one couldn’t gain all the benefits alone; the other party also required fair treatment. Moreover, the family’s future was at stake, necessitating careful decisions.

“If I stay in the capital, the Duke’s family is the best. But that’s based on conditions, not reality. There could be issues.”
“Minor inconveniences may arise. But they are better than other noble families. What family is as wealthy as the Duke’s?”
“Are we living in the North because we are wealthy? We protect the empire’s borders out of duty and responsibility. Wealth doesn’t guarantee happiness.”

Jaior pondered those words and chuckled. Alter had endured the harsh northern life despite his frailty. Although he had never faced the icy storms or participated in battles, just staying alive was a miracle.

“……So, you want to marry a lesser family?”
“A family you’re comfortable with. Isn’t my presence in the capital enough?”