I bet Hyeonjae will end up trying to kill Jingi later lol Or maybe kill mc too if he's jealous or gets rejected too many times. For Jingi I think if he becomes too attached to mc and tries to take him away or keep him 'safe' from his younger bro, Hyeonjae will feel betrayed because of this promise and will try to hurt him.
I bet Hyeonjae will end up trying to kill Jingi later lol
Or maybe kill mc too if he's jealous or gets rejected too many times. For Jingi I think if he becomes too attached to mc and tries to take him away or keep him 'safe' from his younger bro, Hyeonjae will feel betrayed because of this promise and will try to hurt him.