I been think that too. Why is Yahwi here if Jooin and Cain are soulmates. Maybe he's supposed to be an obstacle. Someone to show what Jooin doesn't want, make Jooin relaize that he doesn't need someone like Yahwi in his like. So they showed the negative before the positive so Jooin can recognize the difference ?? Idk I trying figure it out too
i think to realise he had eventually done the same thing to cain that yahwi did to him, and now he realises his mistakes and cain chase arc begins.
at least i hope that is the case.
it also could literally just have been the fact that the author saw how well received cain was and how hated yahwi became that they just decided to switch the endgame midway.
I don't think that's case anymore because both are equally liked and equally hated. The author stated that no matter who endgame is they will still get hate. So they didn't change the endgame and it's still the exact same as before. And seeing the drama on twt I agree with her. Things probably didn't change.

bitch you're the one who told him to!! crying and moping every time he tried to do anything... YOU made him, AND yourself miserable! now you're upset that he left??
also, I personally liked the backstory. They're clearly soulmates so.. wtf is Yahwi even doing here? give him another love interest, and one that's more healthy please!
at this point, Cain should just come to me. I'll make him happy I promise!