yall I'm pretty sure the female lead is the same soul in the second season, just a new(the original Natsu's) body. So just like mu-doek is natsu, natsu will still be natsu.
I have a feeling that yi jin is adopted since the dad said that he was his greatest consolation from ten years ago. The child might be his and his real surname might be kim. Hopefully so because I want a happy ending.