Night's King

"He had been the thirteenth man to lead the Night's Watch, a warrior who knew no fear. And that was the fault in him, for all men must know fear."

- Old Nan

Night's King, also known as the Night's King, is a legendary figure in the A Song of Ice and Fire and Game of Thrones mythos. According to the legends he was the thirteenth commander of the Night's watch, who sided with the Others. He's considered only a legendary figure questioned by the archmaesters of the Citadel.

In the TV series adaptation he is preceded by the Night King, the first leader of the White Walkers.

After his defeat, all records and informations about him were destroyed, his name was forbidden, and later forgotten. He was from the North, and some people believe the Night's King was a Bolton, a Magnar of Skagos, an Umber, a Flint, a Norrey, or a Woodfoot. Old Nan thinks he was a Stark, brother to a King in the North.

History
According to the ancient legend of Westeros, Night's King lived during the Age of Heroes, not long after the Wall was complete. He was a fearless warrior named the thirteenth Lord Commander of the Night's Watch. Later, he fell in love with a woman "with skin as white as the moon and eyes like blue stars". He chased her and loved her though "her skin was cold as ice", and when he gave his seed to her he gave his soul as well. Night's King brought her back to the Nightfort and after the unholy union, he declared himself king and her his queen, and ruled the Nightfort as his own castle-kingdom for thirteen years.

During the dark years of his reign, horrific atrocities were committed, of which tales are still told in the north. It was not until Brandon the Breaker, the King of Winter, and Joramun, the King-Beyond-the-Wall, joined forces that Night's King was brought down and the Night's Watch freed. After his fall, when it was discovered that Night's King had been making sacrifices to the Others, all records of him were destroyed and his very name was forbidden and forgotten. It is likely this led the lords of the north to forbid the Night's Watch to construct walls at their keeps, ensuring the keeps would always be accessible from the south.

Maesters are skeptical of the legend, thinking the Night's King's corpse queen was possibly a daughter of a Barrow King from the barrowlands. Some fan theories link her with the Others because of her description.

According to the legends, Night's King appeared only after the Long Night, the Battle for the Dawn, and the creation of the Wall. Before Night's King reign the Others already fought against human multiple times. Also the Others appeared centuries after the war between the First Men and the Children of the Forest.

A Storm of Swords
While travelling to the Wall, Bran stops at the Nightfort with Hodor, Jojen and Meera Reed, and Summer. He recalls stories told to the Stark children of Night's King and the Nightfort by Old Nan. She suggested that he was Brandon Stark the Builder.

A Feast for Crows
While talking with Jon Snow, Samwell Tarly uses Night's King as an example of legendary figures questioned by archmaesters of the Citadel.

Trivia

 * There is speculation that the Night's King may be connected to the Starks or the Boltons.
 * Book readers have noticed some similarities between the Night's King and Stannis Baratheon:
 * Both of them are described as fearless men. The difference is that the Night's King chooses love over duty, while Stannis never abandons duty.
 * The Night's King fell in love with the Night's Queen and gave his soul to her through their unholy union. It was stated, also in the show, that Stannis is not in love with Melisandre but she's the only one who can appease his nightmares caused by blood magic. Ever since Stannis needed to have sex regularly with her. Also, while it's implied the Night's King was completely under control of the Night's Queen, Stannis is not under Melisandre's control, although he tends to listen to her often, but only after reflecting about her ideas alone for sometime and always threatening Melisandre to punish her if he doesn't get any results. The creation of shadow assassins through the sexual intercurse between Stannis and Melisandre is referred as an "unholy union".
 * The Night's King took the Nightfort as his seat and started to make horrible human sacrifices for his queen and the Great Other, including children. Since his defeat the Nightfort remained abandoned, until Stannis took the Nightfort as his new seat. Stannis can accept human sacrifice for R'hllor sometimes, but only if it's also an execution of a criminal. In the TV show version he's even more willing to accept it, burning alive his brother-in-law and daughter as well.