While one is historical and the other modern day, both dramas have a determined FL who is a single mother (either biological mother or aunt/adoptive mother) to a precocious little boy. The child takes a liking to the ML at the beginning and calls him his martial arts disciple. The ML has never met the little boy before but is related to him (father vs. uncle) and quickly steps into the role of father, all while falling in love with the FL.
Both dramas are very similar in pacing, plot, and feel. The characters are also similar, featuring a talented, independent FL on a quest, a supportive ML, a single mother (FL vs. SFL), and a child looking for his father (who doesn't know he exists) who bonds with the adults around him who all try to protect him.