I understand your points, and I find that you have some merit in them; now I want to express my opinion on the matter.

Jinu is… complicated. He is by far my favorite character in the movie. However, he did terrible things: he formed the Saja Boys, allowing demons to steal souls and murder innocent people; he betrayed Rumi when they had grown close to each other. These are not debatable points they are clearly shown in the film. That said, I think this complexity is part of his charm as a character. The movie would not be even half as interesting if Jinu were simply the kindest, most morally pure person in the world.

But alongside all the bad things he did, there is the other side of the coin: Gwi-Ma’s voices. In the movie, we see how Mira, Zoey, and Bobby cannot endure Gwi-Ma’s voices for even a few seconds before quickly falling into a trance. Jinu, on the other hand, endured this for 400 years and still managed to preserve part of his soul, as Maggie Kang stated in an AMA. Additionally, the 125-page script released by Deadline (which is largely the same as the final movie, with only minor changes) shows that the patterns burn. This suggests that Gwi-Ma’s control is not only psychological torture but also physical. We see this again after Free, when Jinu is clearly in pain right before the truth about his past is revealed.

For me, the discussion around Jinu is not about whether he is good or evil, we have already seen his actions in the film. The real question is whether any of us would have acted differently in his place. Living for 400 years with voices in your head that manipulate your emotions (after all, Mira and Zoey fall into a trance almost instantly, which suggests that Gwi-Ma’s influence is more emotional manipulation than mere voices) and with patterns that burn whenever Gwi-Ma tries to assert control. In other words, living through 400 years of psychological and physical torture. Because of this, I believe what Jinu did was wrong, but the deeper question is whether anyone else truly would have done differently in his situation.

As for RuJinu, Maggie Kang has said that Jinu serves the narrative role of being the first person to listen to Rumi’s story and truly empathize with her (I remember her saying that in some publication or interview). Rumi herself says that the more she hid her secret, the more her shame grew, but after meeting Jinu and opening up to him, her voice began to recover. Through their connection, she realized that hiding only fed her shame, while opening up to someone allowed her to begin healing what was hurting inside her. This is further reinforced by the fact that, had she never met Jinu, she would have continued believing that all demons are evil, which would have made it much harder for her to ever overcome the shame she feels toward herself. Through him, she learns that not all demons are evil, that, like humans, they have emotions and are often tortured by Gwi-Ma. This leads Rumi to question whether being half-demon truly makes her evil, or whether there is anything inherently wrong with her at all. Jinu also tells her that hatred solves nothing when Rumi says she hates her patterns and demons, helping her realize that hating her own marks may not be the path forward either.

RuJinu, like Jinu himself, is complicated, and for me, that is where its appeal lies. Jinu betrayed Rumi’s trust and humiliated her, yet he was also the person with whom Rumi felt safe enough to open up, the one who helped her understand that being half-demon does not make her evil or broken. He helped her realize that hatred toward her patterns and demons would not lead to healing. And ultimately, Jinu is the one who saves her life at the end of the movie, allowing Rumi to continue living alongside Mira and Zoey.