Melina Asli

Both are xianxia
Both are about love between master and his student
ML is cold, strong, sly and cunning, most of the time poker face
FL is smart and little by little become strong

From same director and screen writer
ML sacrifice so much cus of Fl fortunately FL is not naive like someone we know...
Forbidden love with good amount of angst and sweat moments.
ML is demonic immortal and he is kinda gray and even sometime he can be black...

From same novel writer
Strong ML, Strong FL
Let's say both have writers same writing style and it's more focosed in Main CP's story than extra thing.
ML in both is prince

Both are:
+Female-centric
+Reverse Harem (Multiple MLs)

ML in TMWTCR is King who want to gather power so can make peaceful life in country especially to FL. His personality is kinda like CX.
SML is a villain with two different personality, Which he use his different identities to trick others and run his plans. His personality and love story is kinda like XL.
TML is FL's bodyguard with unspoken feeling who is always around FL.

Both are:
+Female-centric
+Reverse Harem (Multiple MLs)

ML in TMWTCR is King who want to gather power so can make peaceful life in country especially to FL. His personality is kinda like CX.
SML is a villain with two different personality, Which he use his different identities to trick others and run his plans. His personality and love story is kinda like XL.
TML is FL's bodyguard with unspoken feeling who is always around FL.

From same author in same universe.
Dashing Youth is prequel of The blood of youth and all of these dramas are in same universe.

Both dramas are in same universe.
Tales of dark river is spin off of blood of youth and tells a story about assassin organization that had some parts in original story.