Ran Tianqi only has two children, the eldest son Ran Tianyou and the daughter Ran Susu.

Ran Tianyou is four years older than Ran Susu, born in China, when he was three years old, his father was invited by his friend Yamaguchi, who was also a demon hunter, to take his mother and him to Japan to continue the career of demon hunters, and the following year he had a sister Ran Susu.

The brother and sister have an excellent relationship, and in the most innocent childhood, they also had the idea of being with each other forever, like many brothers and sisters. But there is a huge difference in the talents of the two brothers and sisters as the descendants of the demon hunter family, and the difference in talent will affect the development of abilities such as formations, spells, and battles in the future.

Ran Susu had already caught up with her brother Ran Tianyou, who was eight years old at the time, since she was four years old, and when her brother entered a bottleneck in his studies as a demon hunter, her ability was still rising in a straight line. When Ran Susu was just ten years old, her father Ran Tianqi decided that she would succeed him in the future and become the next successor of the Ran family.

Perhaps in the eyes of others, as the eldest son, Ran Tianyou must have endured great pain and pressure because of this, but in fact, he did not envy or resent his sister, he had already made up his mind, even if he had no talent, he would continue to grow stronger through diligence and hard work, so that he could protect her as his sister's right-hand man in the future.

That year, Ran Tianyou was twenty-two years old, and Ran Susu was just eighteen years old, with a flower-like age and good looks, making her a girl who everyone loved. But also because she is too junior high school in all aspects, it has also created her competitive personality. Ran Tianyou knows Ran Susu very well, so he always protects her as much as possible.

One day, Ran Tianqi suddenly received a commission from a wealthy businessman in China, who did not hesitate to spend a lot of money to invite the Ran family to help investigate a bizarre case that happened to his daughter. The rich businessman only got this daughter in the year of the sixtieth birthday, and naturally regarded it as the pearl in the palm of his hand, and he was pampered, but his daughter had just been admitted to a famous art academy in China, but he accidentally disappeared when he went to the Yongchuan Forest to sketch with his classmates. Although the police have characterized it as an ordinary disappearance case, there has been no breakthrough in the case. The mysterious disappearance of a female college student was reported by many media outlets, and for this reason, the forest became a forbidden place for a period of time.

As the police were unable to determine the reason for his daughter's disappearance, the wealthy businessman was in a hurry to find a number of private detectives to investigate from the other side. One of the private detectives found a legend about the Yongchuan Forest from the locals, and it is said that there is a road to the demon world in that forest, but because the entrance to that road is erratic, ordinary people cannot notice it, but occasionally someone will stray into it and get lost.

At first, the wealthy merchant thought the legend was nonsense, but as time went on, he began to believe in all kinds of possibilities. When it comes to the demon world, it naturally reminds wealthy businessmen of demon hunters, since it is difficult for ordinary people to find their way to that world, then they can only find these unusual people to help. After tossing and turning, he contacted Ran Tianqi, who had crossed the ocean, the Ran family is the most famous demon hunter family in the world, and the family history can be traced back to the Tang Dynasty, although the price is countless times higher than those demon hunters in China, but it is a drop in the bucket for rich businessmen.

Originally, Ran Tianqi wanted to send Ran Tianyou to collect information first, after all, Ran Susu was still young and a girl, so he couldn't rest assured when he went out alone. However, at the time, Ran Sosu and Yamaguchi's daughter Keiko were the most formidable competitors among demon hunters of the same age, and she always wanted to prove her strength by completing more challenging tasks, so she took the initiative to ask her father for help. However, Tianqi couldn't resist his daughter, so he only agreed to her, and Ran Tianyou stayed in Japan to deal with the various commissions that had been received there.

However, Tianyou would never have dreamed that this trip would completely change his sister's fate. Although her sister has shown extraordinary compassion for the ghosts since she was a child, she should know in her heart that they come from two completely different worlds from her, and that feelings of love and hate should not exist between her and them.

He thinks that the reason why his sister fell in love with the so-called lord of the demon world was entirely because he did not resolutely choose him to take over the commission of the rich domestic businessman, if he had been more resolute at the beginning, his sister would not have returned to China, let alone ushered in the fate of death.

The night before his sister left home, after he helped her take care of her bags, the two sat side by side on the table that stretched from the living room to the courtyard, each holding a cold can of beer, looking at the bright moon above his head and the flowers and plants swaying in the courtyard in the wind, and did not say a word for a long time.

Still Ran Susu couldn't help but open her mouth first, she patted Ran Tianyou's shoulder and said, "Don't cry with a face, brother!" It's not handsome anymore! ”

"You, be careful in everything when you go out, don't always be stubborn, and don't care about other people's affairs! And the youkai are good at disguising themselves, don't easily believe their rhetoric! What the eyes see may not be true, so use wisdom and reason. Ran Tianyou shook his head and instructed, and then took a long sip of beer. He knew that no matter how much he said, he couldn't change his sister's personality, but he still couldn't control nagging her over and over again.

"You know, in fact, I overheard Uncle Yamaguchi and Dad talking that day, Keiko and you are finally getting engaged." Ran Susu said and winked at Ran Tianyou.

"Are you clearly eavesdropping?!" Ran Tianyou smiled a little shyly at first, and then said, "Yes, she has always been very good to me, anyway, sooner or later she will get married, instead of marrying a woman she doesn't understand, it is better to marry Keiko, are you right?" ”

"What! If you marry Keiko with this attitude, I won't agree! She's a good friend of mine, you have to be nice to her! Ran Susu suddenly narrowed his eyes and shouted.

"Aren't you competitors?! When did they become good friends again?! Ran Tianyou was a little surprised by her overly violent reaction.

"From a very young age, we have made an agreement that we will take each other as the goal of competition, and neither of us will be left too far behind by the other, otherwise we will lose our qualifications as friends."

"Your friendship is so strange!"

"So I cherish her very much, and you have to cherish her too, you know?"

"Hey, how did you become preachy to me?!" Ran Tianyou frowned and said. Only then did he realize that he was going to talk to his sister more about the precautions of being alone, but he was educated by her.

"I'll take care of myself, I won't be stubborn." When she said this, Ran Susu stared at Ran Tianyou very seriously, but soon she laughed mischievously again, "But brother, you also know, how strong your sister is, even if you don't have to be strong, I'm invincible, hahaha!" ”

Ran Tianyou was just about to teach her a lesson, but saw her suddenly lift the cold beer can in her hand and stick it to his mouth, making him speechless and helpless. He cherished her from the bottom of his heart, and if he could choose her, he would even want to die in her place.

Although he later married Yamaguchi's daughter Keiko and also had his own daughter, Ran Mingzhu, the guilt in his heart for his sister has always been indelible, and this guilt is like a wound that can never heal, and this wound will burst open and bleed from time to time, making him miserable.

He kept every letter his sister had sent back, and there were some of the developments in her investigation at that time. Ran Susu believes that the daughter of a wealthy merchant was robbed by the famous yokai Rakshasa Mother, a monster who likes to eat the hearts and blood of human girls to maintain her youthful appearance, and she has found some hard evidence to prove her point.

Among them, the rich merchant recognized that in the cave where the great monster Rakshasa Mother used to hide, she found the clothes and backpacks that the rich merchant's daughter was wearing when she disappeared, and brought them back to the rich merchant, and this commission came to an end.

Although Ran Susu's letter did not directly indicate this, Ran Tianyou could also read that the reason why she was able to enter the hiding place of the Rakshasa Mother who existed in the other world was because of the help of the Lord of the Demon Realm, that is, her future husband Ouyang Xueye. And this Rakshasa Mother happens to be her husband's enemy, and the subordinate of the monster who caused her eventual death. So, he decided to start with this clue and go alone to find his sister's killer and avenge her.

He left his wife and daughter, returned to China, and began to investigate under his own power, and at that time he stayed in the Tulip Apartment at No. 53 Pufang Road. At first, he used his knowledge to try to find the way to connect the demon world and the human world, but he never succeeded. Later, he suddenly had a wonderful idea, which was to set up a lock demon array as a trap in the Yongchuan Forest where the monsters had appeared. He thought that once the youkai were caught by him, and then forced them to lead the way for him, he would naturally be able to find the mysterious entrance.

In a flash, his lock demon array has been cast for a while, but no monster has been caught, and in his disappointment, he is still looking for other clues. It's only strange that Ran Susu was bent on protecting her husband and the world that belonged to him, and there were too few clues about the demon world and the place where she lived.

Just a month after he moved into the Yujin Apartment, his lock demon array finally gained something, I don't know if it was a coincidence, the little ghost he caught turned out to be the ghost slave of the Rakshasa Mother. Under the guidance of the ghost slave, he finally knew how to enter the demon world, but the ghost slave did not obediently take him to meet the Rakshasa Mother, but took him to a hotel called Sparrow in the royal city of Yongchuan.

His identity was soon revealed, and he was almost caught by the innkeeper, Lady Lan, who was lucky enough to escape back to the world, although he knew that he had been targeted by the monster who had killed his sister Ran Susu, but he was unwilling to give up this only chance to avenge his sister, so he hurriedly handed over the diary of the various investigations he had carried out after returning to China to the innkeeper, and then returned to the Demon King City. That night, some of Mrs. Lan's subordinates infiltrated the Tulip Hotel to cut down Ran Tianyou, but they couldn't find any trace of him, so they had to destroy all his belongings.

Since then, Ran Tianyou has lost contact with his family, and although most people think he is dead, his wife Keiko has another statement, after losing her good friend Ran Susu, she can't accept that her husband Ran Tianyou will also die. She believed in her husband, in her eyes, her husband was strict in his work, and skilled in all kinds of demon hunting knowledge, and with his love for herself and her daughter Ran Mingzhu, he would not leave this world so easily.

But why didn't he come back? Or even cut off contact with everyone? Keiko couldn't say why. In the days of waiting for her husband's return, she managed the business of the Yamaguchi family and the Ran family alone, while raising Ran Mingzhu as an adult.