TRIGGER WARNING: Mention of murder/death.
Wang Yo was birthed to King Taejo of the Goryeo dynasty and Queen Sinmyeongsunseong of the Chungju Yu clan (Queen Yoo). However, the queen wasn't the king's first choice. Nor was she somebody he respected and/or appreciated. He cared more about Queen Hwangbo (his 4th queen) more than anybody else as she treated him with the affection and respect he believed he deserved. From a very young age, Wang Yo remembered his mother always running after the King, creating scenes and drama because she didn't get the attention she needed, even though what she truly needed was to become the King's only Queen. However, it wasn't possible as it was normal for each king to have multiple consorts. Queen Yoo just couldn't accept it. Her attention wasn't on him. With the Queen birthing princes Wang Yo, Wang So and Wang Jung in order of age with Yo being the older one, she knew that Wang Jung was far too kind and innocent for him to be manipulated, thinking of him as quite weak. Hearing from the king's astronomer that Wang So was born under the star of excellence and king, she bet all of her cards on him. She used him the best she could. She tried brainwashing and manipulating him, pushing Yo aside and making him feel unimportant. Yo was raised by court ladies, without having a mother or father figure by his side, both parents of his ignoring him. Even the king had cared more about Wang So, and the Queen knew exactly where to step on, in order to make the king do what she wanted.
During one of her usual scenes, she hurt her own son, Wang So. She created a scar for him and they all knew quite well that with a scar, he was prohibited from being king. They sent him away to protect him from the Queen but also because they were ashamed of the boy. That's when the Queen's last resort became Wang Yo. He was born under the star of treason and she knew that it was as powerful as excellence. She gave him the love he, so desperately, craved for and he immediately wrapped himself around her little finger, doing everything and anything she asked of him. She feigned all of her outrageous desires on her wanting the best for him, even though all she truly needed was the throne and power alongside fame and all he needed was to be loved. And since his father wouldn't even bat an eyelash towards him, at least, his mother may have been able to. Poor Yo fell right into the trap of his mother, allowing her wholeheartedly to manipulate and brainwash him into thinking that everybody wanted to hurt him and they didn't deserve the throne.
He grew up alongside many brothers, however, most of them respected him because they feared him, knowing exactly what he was aiming at, and yet the only brother that truly appreciated and loved him, wasn't even his own blood brother. He was a half-brother of his, the son of the woman his mother despised. They were close and had similar interests. They played well with one another and were both boys of education and knowledge, having a knack for anything that had to do with reading, writing, or painting. They'd spend countless hours in the library, just perusing through books and reading until late night came that they would retreat after having some relaxing tea and promising that they'd be by each other's side like true brothers. Of course, upon the queen learning of this newfound friendship, she immediately cut it down, manipulating Yo to an extent where she made him believe that he needed no one and that everybody around him was out to get him and his dreams. He had such a weak character and he craved for so much love that he pushed everybody away, including his own blood family, aiming for nothing but success and being the trustworthy man by the king's side, closing him deals and alliances as opposed to the rest of the princes.
As the time passed and the Crown Prince was getting closer to becoming King, the Queen's desire for her son to excel only became more imminent and she was forcing her son to make rushed actions, ending in people being cautious around him and not easily trusting him. Upon Wang So's arrival, the Queen only became more agitated, considering him a threat since the king seemed to lean closer to him. Her agitating moves and personality reflected on Yo's actions. It was as if the Queen was using him like a mask to hide the fact that it was her behind her moves - as if he had been hypnotized and had no free will. When he had asked of Wook's sister to be his and become his consort, she refused, which dealt a huge blow to his self-esteem, especially since she had been his type and he knew that with her, they'd make a very powerful couple and strike success as they were both sides of the same coin. However, seeing her choose Wang So over him, only fueled his hatred towards his brother. And they would often clash with one another as it was only normal.
Wanting to bring the rain by sacrificing and being the one who does it, Yo was supposed to be in charge of it, and that's how he would unofficially become king. Of course, with So beating him to it and carrying the rain even though it was against tradition to have a man with a scar as king, that's when Hae-Soo chimed in. She created make-up and placed it on So's cheek, hiding the scar. With Yo ultimately failing, he placed two targets on So and Hae-Soo, unable to turn a blind eye on the real threat. At the same time, upon the Queen learning of such disaster, that's when she first physically and mentally abused Yo by slapping him. For Yo, it was like a wake-up call. But a destructive one. Because everybody knew he was a ticking time bomb. He yelled at her, saying how he also had a right to make a mistake, being shocked that, even then, she didn't care about slapping him, she only cared about their next move. After that, he left and never looked back at his own mother, but everything that he was bottling up, finally exploded. He made rush moves, he started killing people, though he didn't touch his own blood. He became the third monarch of Goryeo, becoming king in a wake of dead bodies and bloodbaths that he created. He didn't care for his people, nor for the land. As long as he was King. For as long as he reigned.
But that's when it started; paranoia. The guilt eventually got to him. The people he killed became his own downfall as they wouldn't let him sleep, eat, take care of himself and he lost an awful amount of weight, looking like a dead man walking throughout the kingdom's corridors. The spirits of all those he killed, his own family, chased after him. They kept torturing him. Until one day, he was found in his room, dead. Many within the kingdom blamed Hae-Soo, thinking she had poisoned his tea. Others cheered for her and jumped with joy - mostly his people, who considered him the worst monarch. The true reason was a heart-attack. Somewhere between poor health, losing weight, needing psychiatric help he never got, and feeling paranoid, his heart couldn't take it. At least, before he died, he signed a scroll with the royal seal, helping Hae-Soo prevent the inevitable upon So becoming the next king in line.
In the modern era, Wang Joon is a man of poor origins. His parents weren't known and were everyday parents. They never had the luxuries he had as king. His father had suffered from a stroke, deeming him unable to communicate with the world and whenever he talks, he either talks nonsense or they have him locked inside the house so he doesn't go missing. He, no longer, has a connection with the outside life away from home as anything that needs to be done within the house or even when it comes to errands or groceries, it's Yo's business. His mother, on the other hand, due to a car accident, lost all power and feel of her leg, deeming her disabled on one leg, even though the other is fine and she limps, using a walker. Their pensions usually are spent for medicine and doctor visits and so the rest of the bills and the expenses fall on Joon's shoulders. For years now, he has no money for himself as he's helping out his family, living in a run-down house that's been there for years and generations on end, which also means that there are a lot of damages. Damages he can't exactly patch up. And no matter how many times he tried cleaning the moss from the walls, he simply just couldn't do it. He has been overly exhausted mentally and physically while he's running to make ends meet. Because of the house's bad state and the moss, he has developed respiratory issues and a bad cough from time to time.
Joon, however, having the royal, bad blood inside of him, he found his own release. He thinks he's being a hero by becoming a vigilante. He didn't truly know when it started, however, after some time, he started chasing after the news on criminals and crimes. On serial killers around Korea and their MO. He has been researching, exploring, and finding as much information as he can, posing as a fake journalist from an imaginative newspaper to gather more information. When he knows enough, he goes after serial killers, killing them with their own MO, thinking that he's saving the world, not knowing that he, himself, had become a serial killer. The police is often referring to him as Serial Killer X - where it all starts, the origin, so the police have to protect criminals and serial killers to catch another serial killer.
In the meantime, when it comes to money since Joon only finished high school and graduated from there, he could find a job in a courier service as a package delivery man within South Korea. Becoming an employee of the month and getting raises for having one of the best records for delivering packages, it shows just how much of a perfectionist he is. As he has no car - having only a bicycle, he moves around with the company car, which he has for many hours within the day because of the delivery of packages, and with that money, he's able to give money to his family and place the food on the table. With him having nightmares of Goryeo throughout his childhood and even more imminent now, he has always felt disconnected from his family - as if he never belonged there - however, often shook the thought and told himself he has been thinking nonsense.
In the same breath, he has been achieving high and mighty goals, wanting to become the president of South Korea, though such a dream is absolutely fruitless, knowing that he doesn't have what it takes to do so.
​
In my verse of the show, I explore the time-traveling side of it, even though by the end of the drama, nothing was said for certain (whether or not it had to do with time travelers). I'm simply exploring this side because it makes more sense. When Hae-Soo traveled to Goryeo without knowing what had happened, of course, her mind never got to the point where she thought she was a time traveler. She doesn't think that now, either. When Wang Yo died on the same day he was born, the time-traveling powers began counting down, reducing Hae-Soo's time in the Goryeo era as dying the same day you were born is a rare occurrence (not even sure it ever happened, tbh, I just wanted to spice it up). When Hae-Soo died in Goryeo since it wasn't supposed to happen, it was as if the time machine had broken and instead of only Hae-Soo being thrown back into the present day, all princes were thrown in the present day. All in different parts of Asian countries. All have been getting nightmares of the Goryeo era, of who they are, of each other yet, of course, they all have their families (some have spouses or girlfriends) and they have their whole life laid in front of them, so they shake the idea off as simply a nightmare. They will remember everything only if they all meet one another in the same room and when that happens, they'll be thrown back into the Goryeo era and have a second chance to rewrite history. However, they will have to choose; take their loved ones with them and risk them dying or leave them present-day and risk never seeing them again and possibly not ever existing again present time. Until they all meet in the same room, even if they see one another, they may get flashbacks or memories but it would be like an incomplete puzzle piece.