Someone asked this in one of the pages I follow
So here’s my take on this
BD posted a teaser of Seungwon’s appearance in season 4 before in one of her tweets
And in this season, we also see Heena, taking Seungho’s side after she’s been saved
Since Seungho and Na-Kyum are mirrors of each other, we can also assume that even their respective families are mirrors as well
With Seungwon now in the picture, him having shown to appearing as a defiant younger brother who’s messing up his older brother’s household, we can take this as his version of Heena’s first appearance in the manhwa, where she raised ruckus in the Yoon household
Notice that in both cases, they barged in under the assumption that Seungho had commited a crime. For Heena, she assumed that Seungho kidnapped Na-Kyum, whereas now, Seungwon assumed that Seungho burned down the shaman house after the murders of the noblemen
In Heena’s case, Na-Kyum defended Seungho’s name and told her that she’ll stay with him despite the “evidence” that Seungho committed the crime of murdering In-Hun
And we can assume that in Seungwon’s case, Na-Kyum will also do the same to Seungwon. We can assume that Na-Kyum will not believe that Seungho murdered the noblemen, as Na-Kyum had been brainwashed that the night of the kidnapping was merely a nightmare, and I think that in his delusion of wanting peace to remain in his heart, Na-Kyum will believe it for some time unless he sees or hears evidence that Seungho did commit a crime
Seungwon can come off as someone who is hardheaded just like in his first appearance when he barged in on Seungho’s bedchamber despite even being told off by Kim, and we can assume that Seungwon has been brainwashed by Chang-Hyeon that his older brother had committed a crime and must be punished before officials find out, because a nobleman committing murder of another noble, let alone a bunch of noblemen, can equate to the annihilation of the criminal’s entire clan. Additionally, the sacrilegious act of defiling and burning down a shaman house along with a sacred tree, warrants hatred from the Shamanistic Joseon people, who considers these elements as beings not to be destroyed, as doing so would incur the wrath of heaven upon the entire village or even the nation itself. With this knowledge of the gravity of the situation, this is why Seungwon orders the guards around in such haste in case any of the servants have destroyed any evidence unknowingly
Seungwon has yet to know though, that the biggest evidence would be in the form of Na-Kyum himself. The trauma is still fresh in his mind even after a month under Seungho’s care and supervision.
And just like the brainwashed Heena who was convinced that In-Hun had been kind to Na-Kyum, Seungwon would initially not likely to believe that his brother didn’t burn the shaman house down, as it’s most likely that the info he got had been from his trusted source, Yoon Chang-Hyeon, their father. Who, in Seungwon’s eyes, is most likely his hero who does everything he can to preserve the Yoon family name. Seungwon had most likely been subjected to information that Seungho is a stain on the family and would one day be the cause of their annihilation. And Seungwon is now there at Seungho’s house to “save the family from his brother’s misdeed”. I think Seungwon thinks Seungho “can be saved from his father’s wrath if he can only come clean with his crime”. Judging by the urgency and the calm appearance of Seungwon in chapter 115, I think he wants his older brother’s affection in some way, despite them being estranged. Hence this is why Seungwon might initially come off as an enemy (like Heena did in her first appearance), but is most likely going to be an ally once the truth is revealed to him—that his brother didn’t destroy a holy place and the sacred tree, that his brother committed murder in the name of love
Seungwon, I think, has a heart in there somewhere, a heart that wants to understand why his brother acts the way he does. And yet, his actions come off to Seungho as meddlesome—exactly like how Heena is to Na-Kyum’s life when she found out he was living with Seungho.
For now, I am placing Seungwon as a gray character who’d be most likely become one of SeungKyum’s supporters once the truth is revealed to him—that the bad guy had been his father all along. But I am sure he’ll be having a moral dilemma at that point, it’d be hard for him to believe it at first, just like when Heena didn’t believe Seungho until she gets kidnapped
Which brings me to another theory, that at some point, Seungwon might get caught up in a conspiracy and he’d be wrapped up in something he’s not supposed to see. And just like Heena, Seungwon, too, could get kidnapped—either by Song’s men, or maybe even Chang-Hyeon himself, probably under the pretext that “your brother did this to you and therefore you must kill him”
I think that is the plan that Chang-Hyeon is going to pull off. He doesn’t want his hands dirty, he always gets others to do the dirty work for him. And Seungho’s death could include that. Since the ending of chapter 115 showed Seungho being stabbed, we can assume that it’s Chang-Hyeon’s guard who did this. This coincides with the appearance of Song before In-Hun. The older nobles are looking for ways to dispose of Seungho without linking the crimes back to them—and I think they found their fall guy with In-Hun
Now, I think: Chang-Hyeon made a deal with Song and it seemingly appeared as if they want In-Hun to take the blame under the pretext that In-Hun hated Seungho enough, he hired an assassin to get him killed; but all the while, Song is thinking of something else entirely. I think Song wants Seungwon to take the blame. Song could manipulate Seungwon at some point into thinking that the younger Yoon is helping his brother when in reality it’s not. (Like in the case of Min manipulating Heena into thinking he’ll save Na-Kyum when he did the complete opposite.) Song could take down both the Yoon brothers and Chang-Hyeon in one fell swoop, all the while Chang-Hyeon is unknowingly signing the death of his entire clan to this one devious man
