Yes they are indeed! There is never just one answer when it comes to people and analysing things that including fiction. My analysis now is just one of them but of course there is probably more to come and maybe it changes throughout the story but i like to discuss it with other people and hear others thoughts than just look at it at the “surface”
I completely agree with you, and your analysis made me think about something else: what if the “delusion” also applies to the way the characters see themselves, not just each other?
Especially with Nanjo, I feel like he might have created an image of himself as the rational, responsible person—the one who has to step in, fix things and keep everything under control. And Mokyeon seeing him as a saviour probably reinforces that image. But maybe that’s also why Mokyeon can trigger such a strong reaction from him. Mokyeon doesn’t just create chaos around him; he potentially challenges the image Nanjo has of himself and the role he has given himself.
I also find it interesting that Nanjo seems to soften when Mokyeon admires him, because I don’t think those moments necessarily contradict his irritation. Maybe he genuinely enjoys being seen as someone reliable and admirable, but there is a difference between being appreciated by someone and being turned into their “saviour.” At some point, that role can become a responsibility you never actually asked for.
So I wonder whether part of Nanjo’s reaction in Chapter 38 could come from that contradiction. He might like being important to Mokyeon and even feel protective towards him, while simultaneously being exhausted by the position Mokyeon has placed him in. And if Mokyeon is unknowingly triggering something from Nanjo’s past, that could explain why his reaction feels deeper than simple anger.
Basically, I think you’re onto something with the idea that everyone has their own version of reality. Maybe Nanjo isn’t just struggling with the version of Mokyeon that exists in his head—he might also eventually have to confront the fact that his own image of himself isn’t entirely accurate either. And I think that would fit the whole “borderline of delusion” concept perfectly.
Oh absolutely! My theory is that it can be interpreted both ways. Someone admiring you and looking up to you all the time can actually start to feel like a responsibility, as you said, or even like putting someone on a pedestal, which can make it worse rather than better. And for someone like Nanjo, I can see that doing more damage than good. But that’s also why I think there is something deeper rooted in him, because of how he always needs to have everything and everyone “in check.”
I really think there’s something in his past that shaped the way he deals with uncertainty. He seems to have this instinct to step in and take responsibility before anyone even asks him to, and I don’t think that’s something you develop for no reason. Maybe he learned very early on that things could go wrong if he wasn’t paying attention or taking care of them himself.
And if that’s the case, I can see why Mokyeon affects him differently from other people. He’s not someone Nanjo can simply “handle” or predict, so being around him might bring out feelings Nanjo normally keeps buried.
Yes, I noticed that too. There’s also that chapter where Mok calls Nanjo from the hospital and then mokyeons phone dies. He literally runs there and is all sweaty, that doesn’t feel like a normal reaction to someone he sees as just a stranger. To me, that kind of reaction either comes from genuine worry/stress about someone you care about, or because the situation triggered some deeper thought or feeling in him. Especially when he had already decided that he didn’t want to see or talk to Mok chapters ago. But that phone call alone still kept him “on edge”?
Another scene that stood out to me is when they’re in the car and Nanjo is “scolding” Mok. (I don’t remember the exact words, so correct me if I’m wrong—again, my brain ) But I remember him saying something along the lines of how all those things probably didn’t matter to Mok, and then he keeps going at him, but at the same time we can see his mouth tensing (maybe pressing his lips together or gritting his teeth, I don’t know the exact term). I get the feeling that he might be holding back anger or disappointment, but there’s also something about his expression that makes me wonder if he’s remembering something sad or trying to suppress an emotion. You know that reaction when you’re almost about to cry but you’re trying really hard to hold it back?
It’s all subtle, but when you start noticing those small things, it can make a lot more sense.
YES, exactly And I think what makes those moments so interesting is that Nanjo’s body language sometimes seems to tell us more than his actual words do. He can verbally distance himself from Mok or act like he’s simply annoyed, but then there are these small reactions that feel much harder to consciously control.
That’s why I feel like the author might be deliberately leaving little clues through his expressions rather than directly telling us what he’s feeling. We probably don’t have enough information yet to understand why he reacts that way, but I definitely don’t think those details are there for nothing.
Yep, the author is actually doing a good job with giving out clues, in my opinion. Not every author can do it that way, especially if, like you were saying, she might be doing it deliberately. Like, if she’s basically telling us, “People, think!”
But I’m glad we’re on the same page. I’ve been thinking out loud to myself for days now, trying to analyze everything and figure things out, like my life literally depends on it . And I had no one to share my thoughts with because everyone keeps saying that Mokyeon might just have borderline disorder, while I’m thinking, “No, it might be something deeper.” (Not saying that’s wrong—it could be that he has borderline too—but it just felt too simple to me lol.)
Or maybe I’m just overthinking the shit out of this.
Honestly, i don’t think you’re overthinking it that much. I feel like people can sometimes get attached to one explanation and forget that a story can have several layers to it. Even if Mok does have BPD, that wouldn’t necessarily mean it’s the only interpretation or meaning behind everything.
I think that’s why your theory makes sense to me. You’re looking at the story as a whole and connecting different elements instead of trying to find one simple answer that explains everything. And honestly, just because something has a more obvious explanation doesn’t mean we can’t question whether there’s something else going on too .
Maybe we’ll eventually find out that we’ve been analysing all of this for absolutely nothing , but that’s literally part of the fun. And who knows? In a few chapters, we might be sitting there like, “WAIT… we were actually onto something.”

I’ve read Chapter 38 and creator note like 20 times already because it’s fun, but also—and mainly because of my DLD (yes, the same as Mokyeon; I’m also diagnosed with it)—I have to read things multiple times before I fully understand them.
But here’s what I found, and again, this is just MY opinion.
When reading the creator’s note, she said:
“The title Borderline comes from the word migyeong, which means ‘borderline of delusion.’”
“Being so captivated by something that you can’t see its true nature.”
“Becoming so lost in delusion that you can’t make rational decisions.”
Then she adds:
“So yeah, the title basically sums up the characters too.”
So, if we’re going to talk about this from a character perspective, I think this makes a lot of sense.
Nanjo couldn’t see Sunhwa’s true nature. He thought Mokyeon was the one forcing Sunhwa into things, when in reality, Sunhwa is the freaky one and not submissive at all. Nanjo has this image of Mokyeon being manipulative and yada yada, while Mokyeon sees Nanjo as his saviour, the calmness in his world, etc. And I think all of those perceptions can be considered forms of delusion.
Basically, all of them have created their own picture of each other that doesn’t necessarily match reality.
For Nanjo, he has this rose-coloured image of Sunhwa, while Mokyeon has something similar with Nanjo. So, in my opinion, “Borderline” doesn’t necessarily mean that Mokyeon actually has borderline personality disorder. Instead, it could mean that all of the characters are living inside their own versions of reality, where they interpret and understand each other based on the images they’ve created in their heads.
And then we get to Chapter 38.
I actually don’t think Nanjo is mad or angry at Mokyeon. He’s definitely pissed off and irritated, yes, but I don’t think he’s genuinely angry at him.
And this is where I think the creator’s Q&A about Nanjo becomes really interesting. She says:
“He can show compassion even to his longtime enemy and will never give his left hand, even when shaking hands with someone he dislikes.”
She also says that he grew up as an ESTJ but is now an ESFJ.
Now, I know MBTI personality types aren’t everything, and obviously you can’t use them to explain an entire person, but I still think they can tell us something about how a character is written. And personally, I LOVE talking about this kind of thing and analysing characters through their personalities, so I find this detail really interesting.
Someone Growing up as an ESTJ, especially stereotypically, can mean having a strong need for control, structure, and stability. They tend to take matters into their own hands and can sometimes come across as controlling or overly involved. But that doesn’t necessarily mean they’re doing it because they want to control everyone around them. It can simply be the way their brain works and the way they create a sense of safety and stability for themselves.
And we’ve already seen so many people discussing how Nanjo seems like he needs to know everything, always wants to get involved, always wants to butt in, yada yada.
That is basically very ESTJ-coded.
Obviously, I’m speaking stereotypically here, but I don’t think Nanjo is necessarily butting in or trying to control things just for the sake of controlling them. I think it’s part of his personality and nature.
I also personally believe something happened during his childhood. I obviously don’t know what, but I wouldn’t be surprised if there was some kind of parentification involved, or if he lost someone important to him—maybe through death or something similar. I feel like there’s a reason behind why he has such a strong need to take responsibility and keep things under control.
And this is why, when I say I don’t think Nanjo is actually angry in Chapter 38, I mean it.
Because look at his eyes.
His eyes soften whenever Mokyeon admires him.
Which, by the way, is also VERY ESTJ soft-spot coded. they like bragging and someone to look up to them which *ahem* mok is doing good here. (I also see nanjo as a kuudere.)
And then we have that first statement from the creator saying that Nanjo can show compassion even to his longtime enemy.
To me, that says a LOT about him.
I think Nanjo is actually capable of understanding that there are multiple sides to a situation (might be his esfj side too?) He might be irritated, pissed off, blunt and absolutely done with Mokyeon’s bullshit, but I don’t think he’s incapable of seeing why Mokyeon behaves the way he does. He might just simply be done with this behaviour because maybe he has been through that before in his life with someone or just mentally exhausted since childhood.
You know it’s like when we are angry at something or someone but threw our anger on someone/something else instead, that’s how i see nanjo in this chapter. So there is something else rooted in there and mok might be the one triggering it for him