Bulgasal: Immortal Souls (2021)

The series tells the story of a man-turned-immortal, Bulgasal, who wants revenge from a woman with a mysterious past and present, who he deems responsible for his immortality and miseries from the past 600 years, hoping to free himself from his curse.
?

Lee Heon is the king of Joseon. 7 years ago, when he was a crown prince, his beloved wife died. To this day, he has not been able to get over her death. For the past 7 years, the royal family and government members have tried to get King Lee Heon remarried without success. The nation has also implemented a geumhonryung edict, which is a ban on all single women marrying during this time when the king has not married. People are furious over the marriage ban. One day, King Lee Heon hears of a woman named Ye So Rang, who claims the spirit of the king's late wife exists within the royal palace.

Meanwhile, Ye So Rang is a swindler and claims to interpret marital harmony signs. She is arrested and jailed where Officer Lee Shin Won works. To get out of her predicament, she pretends to be possessed by a spirit in front of Lee Shin Won. During her ruse, she mentions that the spirit of King Lee Heon's late wife exists within the royal palace. She is then brought in front of the king and he asks her if she can really see his late wife's spirit. To survive, Ye So Rang acts like her body is possessed by the king's late wife. Ye So Rang's lies get bigger and more audacious.

Rebirth story, Male and Female lead were past lovers (sort of).. Female lead who doesn't remember her past life when the climax of the show entirely depends on it..., slowburn romance, found family trope.. hunting monsters to protect the Fl, Male lead yearing to leave his monstrous existence and hopes to become a human....the similarities are endlessly)

The series tells the story of a man-turned-immortal, Bulgasal, who wants revenge from a woman with a mysterious past and present, who he deems responsible for his immortality and miseries from the past 600 years, hoping to free himself from his curse.
?

The series tells the story of a man-turned-immortal, Bulgasal, who wants revenge from a woman with a mysterious past and present, who he deems responsible for his immortality and miseries from the past 600 years, hoping to free himself from his curse.
?

In both series the male lead suffer from a curse and the key to lifting the curse lies with the female lead and in process the romance between them

The series tells the story of a man-turned-immortal, Bulgasal, who wants revenge from a woman with a mysterious past and present, who he deems responsible for his immortality and miseries from the past 600 years, hoping to free himself from his curse.
?

delve into themes of revenge, fate, and complex human relationships, offering thrilling narratives that keep viewers engaged.

Yu Jin was raised within the desert tribes of Xiong Nu, although her foster father is a Han. Under certain circumstances, she was forced to flee to Chang'an, the then capital of the Early Han Dynasty, changing her name to Jin Yu along the way. Along her journey, she first meets the calm and kind Mo Xun (aka Jiu Ye, ninth master) and later the handsome, cold general Wei Wu Ji. Jin Yu falls for one of them but is rejected. Will she untangle her love knot? Who will she choose in the end?

Both the series deal with "monsters" but in different ways. Bulgasal is a story of revenge and realisation meanwhile The Guest concentrates more on the horror aspect.

The series tells the story of a man-turned-immortal, Bulgasal, who wants revenge from a woman with a mysterious past and present, who he deems responsible for his immortality and miseries from the past 600 years, hoping to free himself from his curse.
?

Similar aspects /elements between these two dramas. Bulgasal so far has less gore and has a fantasy element to it but both a have romantic relationship and I think people who liked Happiness might enjoy this one too!

Both deal with the theme of reincarnation and have a strong supernatural element.
Only on episode 3 for now but Bulgasal is definitely a bit darker and has less of a romantic side.
TONT deals with deities while Bulgasal monsters.

The series tells the story of a man-turned-immortal, Bulgasal, who wants revenge from a woman with a mysterious past and present, who he deems responsible for his immortality and miseries from the past 600 years, hoping to free himself from his curse.
?

both has strong female lead
both has romantic affection
unexpected twists
exciting to watch, not a single second was boring so far with Bulgasal (currently airing) and till the end with Vincenzo