So far it seems like the transition and shift of dynasty similar to 6 Dragons especially with the mention of Yi Bangwon/Lee Bangwon (Jang Hyuk hyung). Hence I find Seo Hwi similar to Lee Bang-ji & Nam Sun Ho similar to Moo Hyul of of Six Dragons, respectively.
Both dramas are about the rise of Lee Bang Won. Difference is King of Tears is meant to be a more historical take while 6 Flying Dragons adds some interesting characters.
Family, friendship, politics. The plot is brilliant. You won't get tired of the storyline eventhou it mostly was about how to change & establish a new country. Every character have it's important role.
Both series have:
- Good swordmanship.
- Revolution of govenment. SFD (Goryeo -> Joseon), Tnk (Royal family -> Samurai family)
- Greed and hunger of the male lead for power.
- Lots of inspirations and moral values in politics and family.