The Legend: Characters

Hwanung (환웅): A son of the god in the heavenly world. He had longed to live in the surface world for long until he was finally given permission to do so. He was said to have brought three Guardians of the world: the Blue Dragon, the White Tiger and the Black Turtle-snake. After marrying a woman who was born as a bear, he had a son and returned to the Heaven.
His heavenly artifact is the Cheongung (천궁) which normally takes the form of a fancy cylinder and enlarges to form a glowing white bow. It is said to be able to either kill or give life to anyone it shoots. And its destruction means the death of the King of Joo Shin and the unsummoning of the Heavenly power. Before the coming of the King of Joo Shin, it was sealed inside a royal sword named Chumoshin(추모신검), which should release the seal when the heart of the King of Jushin was introduced to it: that is, when it were to impale his heart. When this was done, it exploded in bright light and disintegrated to fine ash-like mystic powder, revealing the Cheongung in it.

The Blue Dragon
BLue Dragon (청룡/Cheong-Ryong): The ruler of the East and the guardian of the clouds, hence the alternative name Unsa (운사/雲師: Cloudmaster).
Its heavenly artifact is a bluish stone that looks slightly like a shellfish. It is said to activate when "The King of Joo Shin 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.

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

The Black Turtle-snake
Black Turtle Snake (현무/Hyeon-Mu): The ruler of the North and the guardian of the rain, hence the alternative name Usa (우사/雨師: Rainmaster).
Its heavenly artifact is a black cylinder that is usually shaped as a long twisted walking stick. It awakens when "The King of Joo Shin feels 'dark rage' in his heart." When it awakens, the time stops along with everything other than its master and the King of Joo Shin, 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 Joo Shin feels 'burning passion' in his heart." It glows in red when activated.