The identity of the Grim Reaper and of Sunny, his romantic interest, has been revealed in episode 10 of tvN's 'Goblin: The Lonely and Great God.' The revelation now creates an interesting challenge in the bromance of Kim Shin, the Goblin and the Grim Reaper.
From all the hints and indications provided, it seems the Grim Reaper may be none other than the soul of Wang Yeo, the king of Goryeo, the very ruler who ordered the death of Kim Shin in his past life. A Grim Reaper (Jeoseung Saja in Korean folklore) is one who has committed a grave sin in their past life. To redeem their sins, their spirits are stripped of memories of their past life and made to serve King Yŏmna, or Yama, the judge of the dead. His task is to collect souls and lead them to the afterlife when their time comes.
It was revealed that the Grim Reaper and Sunny are linked to each other. Gong Yoo's Goblin keeps a portrait of a woman with him, who was his sister in his past life as the king's general. When he held Sunny's hand, he got a chance to take a peek at her past life and it turns out that Sunny is none other than a reincarnation of Kim Shin's younger sister Kim Sun.
Their connection was hinted at earlier, when the Grim reaper cried after looking at the portrait of the mysterious woman in the Goblin scroll. His reaction was the same as when he saw Sunny, played by actor Yoo In-na, for the first time.
The Reaper, played by Lee Dong-wook discovers by touching Sunny's hand that she was king Wang Yeo's queen and Kim Shin's sister. The queen had died by taking an arrow to her heart due to the evil plans of the eunuch Park Joong-Won who had taught and raised the king and manipulated him into killing Kim Shin and his sister.
Also, there's the Jade ring that Reaper gave to Sunny. When he is looking into Sunny's past life as a queen in an ancient era, he sees a hand sliding a jade ring onto her hand. Reaper wants to investigate the ring and asks Sunny to return it to him. When he asks her why she chose the ring, she says it felt like it was hers all along. Well, Samshin, the goddess of birth and fate, played by Lee El had already said that the Reaper and Sunny would meet again and fall in love, as noted by Inquisitr.