hes actually not a replacement. Thats how it seemed at the beginning because Yeojin asked for it to be that way but the story is obviously about Choi Moonhyuk and Yeojin so what are u even saying lmaoo. I suggest you check the raws. The only relationship that was far from lovey is Cha Gang x Yeojin. Cause Cha Gang was a slut, (he said it himself), a mafia guy and obviously did not like Moonyuk romantically. Yeojin actually loves Moonyuk and Moonyuk started to share that feeling. U need to understand they arent teens so dont expect a teen romance here LMAO
Does Moonhyuk have feelings for Yeonjin?
I would believe so, as Yeonjin is the only person who knows about Moonhyuk's past and would accept him for who he is (a flawed human being.) Moonhyuk's lack of affection/expression may be due to their monetary relationship as "master and servant" and developing feelings would be crossing the line. Moonhyuk's feelings for Chagang now are likely to be mere guilt, and this time around, I'm sure he'd do everything in his power to protect Yeonjin.
I understand your point in that Moonhyuk saw Chagang's shadow in Yeonjin. But the difference is that Chagang never viewed Moonhyuk as a romantic interest, while Yeonjin on the other hand genuinely cared for Moonhyuk. (For instance, the time Yeonjin tied himself in red ropes to resemble Chagang, he most likely did so to evoke some human emotion into Moonhyuk- he wanted to see Moonhyuk react)
I feel like Moonhyuk loved Chagang in the past but it isn’t clear how Chagang felt about him. And it does seem like from the raws Moonhyuk is definitely developing feelings for Yeonjin and is quite possessive towards Yeonjin. In the past Yeonjin made the first move for sex but later Moonhyuk starts to initiate sex. I mean this story is a slow burn which makes it so good.
To me yeojin is just a surrogate for moonhuyk ...a replacement for chagang ....their relationship is far from lovey