Night's King

"He hated them—the Starks of Winterfell, the free folk, and the Night's Watch—for what he perceived they did to him. They took away the only things that mattered to him and drove him out of his home in doing so. Now he is one of them and his name is forbidden to be spoken in the North, even by we maesters. And, perhaps, that is for the best. Because, whoever he was, he is no longer. Now, he is only Night's King."

- Unknown maester

Night's King, alternatively known as the Night King, was a Other, the leader of his species, the ruler of the Land of Always Winter, and the commander of the army of the dead. In the faith of R'hllor, he was known as The Great Other, one of two gods and the god of evil, death, and cold, eternally opposite R'hllor, the god of and. The two deities were said to be constantly in conflict with one another to decide the fate of the world. As a powerful, Night's King was one of the faces of to the.

In reality, this male Other was only the second Night's King, having succeeded the first Night's King as the malevolent leader of the Others sometime following the Long Night. He was originally human male, one of the First Men, named Brandon Stark and was among the earliest members of House Stark and, ironically, the Night's Watch. Legend tells that he sought out the Others in hopes of using their necromancy to resurrect the love he had lost at the hands of his brothers in the Night's Watch but returned and claimed the Nightfort as his seat. The Night's Watch joined together with the King-beyond-the-Wall and the King of Winter to drive him out of the Nightfort and back beyond the wall, where he was fully turned into a white walker and became their leader. Afterwards, he was regarded as a mere myth by the realms of Westeros.

Personality and traits
As a human, Brandon Stark was rough around the edges, but ultimately a kind man who was loyal to his family above all. But, as was common of Men, love made him fall, and he saw his exile to the Wall as betrayal from his family, which drove him to seek out the Others and their dark magic. His exile made him cruel, displayed in his sadistic rule over the Nightfort. These sadistic traits were magnified upon his transformation into an Other.

As Night's King, he was not only cruel and sadistic, but also. He did not speak and was singularly motivated by hatred and revenge. He despised all of House Stark, as well as the free folk and the Night's Watch who aided House Stark in exiling him beyond the Wall. Because of what he saw as betrayal-upon-betrayal, Night's King was tireless in pursuit of his destruction of the free folk and the Northmen.

Night's King donned a black armor, much like the rest of his species, and wielded a crystalline falx when entering combat.

Trivia

 * This incarnation of Night's King is an amalgamation of  and the "Great Other" from ', as well as the  from 's ' television series.