This is a very popular fan theory among Korean fans!
In the First Episode, we saw a young king&queen.
The Queen must be Kim Shin’s younger sister (or at least cousin sister) since she was the first one to get shot by an arrow when the King yelled “Kill everyone from Kim Shin’s family.”
And there’s one thing we must point out: THE SYNOPSIS
We now call them the “Grim Reaper” and “Sunny”, but in the early stages, the synopsis called them “Wang Yeo” and “Kim Sun”
And if you’re interested in historical dramas, you’d know that “Wang” is a family name given to the Goryeo Royal Family.
Also if the Queen is Kim Shin’s younger sister, Kim Sun is a possible name for her. (Kim ‘Sun’ -> Sunny)
And you remember when Kim Shin became the goblin and returned to the palace (for revenge)?
This evil subject (also in the first picture) got much older, so we can see that the time has past. So the Young king who looked like a teenager must be in his 20s or 30s. They don’t show us the dead king’s body, and korean fans assume that it is because they’re gonna show Lee Dongwook (Grim Reaper)’s face as the grown up king when the secret of Grim Reaper & Sunny reveals.
So Grim Reaper is the dead king who lost his memory (and probably regretted his choice so much) and Sunny must be the reincarnation of the dead Queen, Kim Shin’s sister. Also the opening clip provides some certainty too.
THEY LITERALLY REWINDED DEAD QUEEN’S TEAR AND THEN INTRODUCE SUNNY
When I first read about this couple, I thought their story was a bit weaker than the main couple’s. But if this fan theory is true, I see why Lee Dongwook contacted the writer first and said he wanted to do it. This story is super awesome!!!!
“I am no stranger to love and I am not waiting for you. Because I believe we will be reborn, because I believe everything, and I believe that we will meet again andsuffer together again.” - Richard Siken, Lillian Gish Goes to Hell
People will do it more if you just let them. They think it’s okay. I didn’t say that to Dr. Do to take your side. If I saw any other person being treated like that at this hospital, I would have done the same.