The Four Guardians

A long time ago, a tribe that respected the tiger and controlled fire called the Ho-jok (Tiger Tribe), ruled the world. They eliminated and assimilated all tribes except the tribe that respected the bear, called the Ung-jok (Bear Tribe). The Tiger Tribe and the Bear Tribe fought, and Hwanung could not bear to see so many people getting killed. He brought the three gods of nature; Baek-Ho (백호, the White Tiger), Cheong-Ryong (청룡, the Blue Dragon), and Hyeon-Mu (현무, the Black Turtle-Snake). He removed the power of fire from the leader of the Tiger Tribe, Gajin, sealed the power into an artifact called the Heart of Ju-Jak (주작, the Red Phoenix), and gave it to the woman he loved; Se-o. However, Gajin was mortally wounded while attacking another tribe, and she seemed to die until Hwanung healed her. This thoroughly convinced Gajin to not make a grudge against Hwanung. When her tribe was revived to take back the power of fire, they didn't listen to Gajin and decided to attack the Bear Tribe. Gajin then slew her tribe's council with her own blade, and escapes from her own tribe and heads towards the Bear Tribe, deciding to become Hwanung's woman. However, Hwanung likes Se-o and declared his love for her, not knowing that Gajin was watching them secretly when this took place. Gajin was infuriated by this and began reforming the Tiger Tribe and attacked the Bear Tribe. Unfortunately, this was the time when Se-o was pregnant, and when she had given birth, the baby was kidnapped by Gajin who offered Se-o a deal to trade her baby for the power of fire. When Se-o refuses Gajin, Gajin responds by dropping Se-o's baby from a cliff, leading to Se-o going out of control and releasing the Heuk-Jujak (Dark Phoenix), even though Hwanung had saved the baby. (Note: Jujak is roughly the equivalent of Phoenix.) Hwanung's subordinates, the White Tiger, the Blue Dragon and the Black Turtle-Snake fought the Dark Phoenix, but they were no match for it. Left with no choice, Hwanung used his Heavenly Bow to kill Se-o, the source of the power of the Dark Phoenix, and managed to seal it once again in the heart of the Red Phoenix. Gajin committed suicide by jumping from the cliff because she now "had no reason to live in this world anymore." Hwanung sealed the powers of the 'Four Gods' (The Red Phoenix, White Tiger, Green Dragon, and the Black Turtle-Snake) in certain artifacts and left them in the care of certain people, telling them that they will wake when the King of Jushin is born. Many centuries later, Damdeok, the reincarnation of the son of Hwanung, was born. Along with him, the artifacts of the guardians of the King were born. Damdeok met difficulties in becoming the king of Goguryeo, mainly because of Yeon Hogae who mistook Damdeok for the murderer of his mother, and his father who turned the king's parliament against him.

 White Tiger (백호/Baek-Ho): The ruler of the West and the guardian of the winds, hence the alternative name Pungbaek (풍백/風伯: Wind leader). Its heavenly artifact is a white twisted piece of metal. It awakens when "The King of Jushin feels 'pure courage' in his heart." The Black Turtle-snake

 BlackTurtle-Snake (현무/Hyeon-Mu): The ruler of the North and the guardian of the rain, hence the alternative name Usa (우사/雨師: Rain master). Its heavenly artifact is a black cylinder that is usually shaped as a long twisted walking stick. It awakens when "The King of Jushin feels 'dark rage' in his heart." When it awakens, the time stops along with everything other than its master and the King of Jushin, enabling the leader of the Four Guardians to identify the King. The Dark Phoenix

 Crimson Sparrow (주작/Jujak): The ruler of the South and the guardian of the fire. It is not a subordinate of Hwanung, and was portrayed as becoming evil when its 'host' is engulfed with anger. Unlike its actual incarnation, it controls fire, resembling Bonghwang (봉황) more than Jujak. Its heavenly artifact is a large red gem orb. It awakens when "The King of Jushin feels 'burning passion' in his heart." It glows in red when activated. For the first time in Korea, a king has been associated with the Four Gods. King Gwanggaeto is generally considered as one of the greatest rulers in the history of Korea. The Four Guardians were found engraved in his tomb (as in any other king's), inspiring the drama.

 Blue Dragon (청룡/Cheong-Ryong): The ruler of the East and the guardian of the clouds, hence the alternative name Unsa (운사/雲師: Cloud master). Its heavenly artifact is a bluish stone that looks slightly like a shellfish. It is said to activate when "The King of Jushin feels 'cold mercy' in his heart." When activated, it can weaken the power of the wielder of fire. It was also shown to speed the healing of its master when in physical contact with him.