Question: who are the six flying dragons?
Answer: Yoo Ah-in as Yi Bang-won (later King Taejong) ...  Kim Myung-min as Sambong Jeong Do-jeon. Shin Se-kyung as Boon-yi. ...  Byun Yo-han as Ddang-sae, later Yi Bang-ji, the best swordsman of Samhan Korea. ...  Yoon Kyun-sang as Moo-hyul, the best swordsman of Joseon. ...  Chun Ho-jin as Yi Seong-gye, (later King Taejo)