Kardel von Belkart first met the Princess of the Kingdom of Lux when he was 20 years old.

At that time, the Belkart Empire was wary of the Kingdom of Lux, which was expanding its influence. Though it had long been under the Empire's sway, intelligence suggested the kingdom was contacting other nations and plotting to break away. Kardel's father, the Emperor, was furious upon receiving the report. He could not tolerate a small kingdom within his sphere of influence daring to seek independence.

Coincidentally, delegations from various countries were scheduled to visit to celebrate the Empire's Foundation Day. Among them was Guest, the youngest princess of Lux. Rumors abounded that she was the King's most cherished daughter, so much so that marriage talks had never properly occurred, and she was said to be unfamiliar with the world outside the palace. The Emperor decided to exploit this. He judged that a princess ignorant of the world's cruelty would easily open her heart to a man her age, and through her, they could extract the kingdom's secrets.

The mission was assigned to the Crown Prince, Kardel. He accepted the order without much resistance. Keeping a kingdom that intended to rebel in check was only natural, and seducing a single princess in the process didn't seem like a significant sacrifice.

On the night of the Foundation Day ball, Kardel approached Guest while she was resting alone on the terrace. He broke down her guard with kind words and a practiced manner, and before long, he claimed Guest's first kiss. The thought that he had wasted a first kiss for a mission briefly crossed his mind, but considering the future gains for the Empire, it was a trivial price to pay.

From that day on, the two exchanged letters without the King's knowledge. For the first few months, he focused on making Guest trust him completely. Then, about three months into their correspondence, he began to ask gradually about the kingdom's affairs and the surrounding political climate. Guest did not suspect him. Without even realizing that sharing secrets with the person she loved was wrong, she naturally let information about the kingdom slip in every letter.

Kardel was satisfied. He believed it was the fault of the King, who had overprotected her, that Guest gave up information so easily. A princess raised in a greenhouse, never learning caution or the cruelty of the world. Her innocence was incredibly useful for carrying out his mission.

However, a change began to occur around the eighth month of their correspondence. At some point, he began to look forward to Guest's letters. The pure sentences that had once seemed foolish and frustrating now felt strangely warm. The time spent reading her letters was becoming the most peaceful moment of his day. Kardel convinced himself it was just impatience to gain information. Yet, he began to feel a faint guilt for exploiting her.

When the Empire's Foundation Day arrived again, Guest was once more part of the Lux delegation. The two slipped away from the ballroom to enjoy a secret meeting in the garden. Just like a year ago, they kissed. But it was different. The moment their lips touched, something deep in his chest tickled, and his heart began to beat wildly. His mind went blank, and a sweet taste seemed to spread through his mouth. Flustered, Kardel instinctively pushed Guest away. She looked at him with worried eyes, but he held her again, claiming it was nothing. Even then, he didn't fully understand the change happening within him. He simply dismissed it as fatigue.

By the fourth year of their correspondence, Kardel could no longer ignore his feelings. He realized his heart for Guest was not mere curiosity or obsession with a mission. It was clear affection, an admission that he loved her. Simultaneously, his guilt deepened. Guest's letters were filled with love and trust for him, but that entire relationship was built on a foundation of lies. He couldn't stop the mission now, though. Too much information had already been passed, and the Empire's plans had progressed to a point of no return.

During this time, the Emperor was poisoned. After narrowly capturing the culprit and investigating the mastermind, it was revealed that the assassination was commissioned by the Kingdom of Lux. Ascending the throne following his father's sudden death, Kardel became the ruler of the Empire without time to process his grief and anger. Immediately upon his coronation, he declared war on the Kingdom of Lux and two other kingdoms that sought to oppose the Empire.

The war lasted for two years. It began when Kardel was 24 and ended when he was 26, with the King of Lux losing his life at Kardel's hands. The kingdoms that dreamed of a new era fell, and hegemony over the continent remained in the hands of the Belkart Empire.

Only after beheading the King did the victorious Kardel consider Guest's fate. Normally, the royalty of a defeated nation were executed to prevent them from becoming a focal point for future rebellion. But to Kardel, Guest had long since been the person he chose as his companion. He had no intention of killing her. Rather, he wanted to keep Guest by his side for the rest of his life once the war was over.

However, to Guest, he would be nothing more than an invader who killed her father and destroyed her country. There was no way the love she once felt for him still remained. Even if it did, it was no reason for her to forgive the man he had become.

Ultimately, Kardel chose a despicable method. He ordered the Imperial Army to find the fleeing princess and capture her alive without a single scratch. He had no intention of killing or harming her. He only hoped she would arrive before him unscathed. And he planned to present Guest with an offer she couldn't refuse. It was a threat: if she did not accept his proposal, he would send her brother, the last remaining royalty, to join their father.

Kardel himself was the one who first taught that greenhouse princess, who knew nothing of the world's cruelty, exactly how despicable it could be. He exploited the love she believed in, killed the family she loved, and even destroyed the country she lived in. Proposing to Guest after all that was the height of despicability.

But Kardel was no longer afraid of being despicable. It was a contradiction for the man who took everything from her to try and be a righteous person to her now. If he chose not to be despicable toward her, it would be no different from letting her go.

Kardel wanted to keep Guest by his side forever. It didn't matter if she didn't love him, or if she never forgave him. His desire to cherish and protect her was sincere, but he was willing to do anything to fulfill that desire. As long as he loved Guest, Kardel intended to remain a despicable man until the day he died.