The Scholar Who Walks the Night (2015)

A love story between the half-human and half-vampire Seon Woo Hyul, who was unable to become human due to a one-day difference over 100 years, and Joo In Hae, a woman who has no humane side and finds true warmth.

Both are supernatural dramas with vampire/vampire-like creatures. The protagonist in both dramas transforms into a monster after a traumatic experience. They both also refuse to turn completely into a monster and stay partly human.

There are not many similarities, only the vibe, but there is no romance in the Kingdom. Both share stories of fighting the unfair government. In both, there are main leads who are fighting for justice and with monsters.

Her iki dizide, sevdigi insan icin insan olmak isteyen biri var ve onlara engel olmaya cal?san varl?klar. Fantastik hikaye ve son bolumde olan taht cok benzedi. Aksiyon ve duygusal sahneler benzerdi

that surreal fantasy vibe,
ethereal male + Female-human
Male fighting off antagonist
Now that I saw the drama poster... It's kind of similar too XD

Both are about a guy who loses his first love and becomes a vampire. The difference is that in Love in Time, the main story takes place in modern times.

Student Mizuki Sakurazaka looks like a boy and is treated like a prince at her all-female Seinoibara High School. She also leads the all-girl rock band Burauerozen. They regularly perform at a venue that allows only women. Akira Shiraishi is a student at the all-male Kaizan High School. He's treated like a princess at his school because of his feminine face. Akira then sneaks in to watch Burauerozen. He confesses his love for Mizuki.

Quiet and gentle, Min Jae Yi is everything a good daughter of a prominent family should be. Engaged to the son of the Second State Councillor, Jae Yi knows that the only way to bring herself and her family honor is to accept her fate, which she does with grace and charm. Devoting herself to learning everything she needs to know to become a good wife and mother, Jae Yi dutifully prepares for the future. Sadly, destiny has other plans for her future. Four days before her wedding, Jae Yi’s family is murdered. With no one else to blame for the unexpected tragedy, Jae Yi soon finds herself the object of baseless and horrifying accusations. Blamed for the death of her family, Jae Yi might not have had much of a future at all, if fate hadn’t decided to intervene. Bringing the lonely crown prince, Lee Hwan into her life at just the right moment, Jae Yi is saved from a dismal fate, but her salvation comes at a price. Plagued by a mysterious curse, Lee Hwan agrees to help Jae Yi, but only if she agrees to help him break his curse in return. Unable to refuse such an offer, Jae Yi agrees to the prince’s terms, setting them both on an unexpected path toward love. But what chance does their love have of surviving when one of them is a former murder suspect and the other is a cursed prince?

This drama is a love story between Kataoka Sakuya, a grim reaper who comes to the human world for the first time, and Mochizuki Nayuki, a woman who lost her father at a young age and has devoted her life to raising her only remaining family—her younger brother. As they meet, they gradually come to understand each other, and slowly, they begin to fall in love. However, a fate that will dramatically change their lives awaits them both…

Scholar Who Walks The Night and The Emperor: Owner of the mask have similarities. Both story is developing the crown prince to become a great King.

It's because there is a cruel person/vampire that stand behind the Kings order and the Prince were forced to serve that person/vampire in order to keep his people save.

In The Emperor: Owner of The Mask there is Daemok. In Scholar Who Walks The Night there is a vampire called Gwi.

L, an angel who’s endlessly fascinated with the human world, gets into trouble when she unthinkingly saves the life of Han Shi Yeong, a man who was meant to die. To make up for her mistake she must guard him on Earth for one hundred days and keep him safe from Hwan, a death god who is required to collect his soul. Both supernatural beings must contend with the knowledge that whichever one of them fails by the end of the hundred days will be erased from existence, and the longer they stay on Earth the further their powers fade and the more human they become.

Both are historical dramas in which the ML is turned into a vampire and later on meets the human FL.

Yamihara Kokoro and Asada Toramatsu live in a town that is quite peaceful, until a serial murder case happened where the bodies all had their blood drained out. Five years have passed but the case remains unsolved. Meanwhile, Kokoro and Toramatsu have been in a relationship for a year, but are unable to get married as they are keeping a serious secret from each other. Kokoro is actually a vampire. However, she does not attack humans and live modestly. Toramatsu is a popular resident in the town and is trusted by many. After getting a divorce, Toramatsu got drunk and went back to his old house, where he met Kokoro, the current occupant. As the two continue to keep their secrets hidden, a horrific murder occurs once again in the town.

Lee Joon-gi in another period piece doing what he does best by bringing the titular lead to life.

Park Yoon-kang is the son of the last great swordsman of the 19th Century Joseon. After the murder of his father and the enslavement of his younger sister, Yoon-kang trades his sword for a Western rifle on a revenge mission to find his sister and those responsible for destroying his life , but he ends up becoming a hero for the people as he fights corruption and his own inner demons.

Lots of action and romance with strong characters both male and female.

=> We see in Scholar Walks at Night episode 17 that Lee Joon Gi acts as 3 characters meeting. In Arthdal, fans are waiting for Eunseom Saya meeting. You can use LJG Scholar Walks at Night scene to see how he will act the meeting scene of Eunseom and Saya in Arthdal.