King Arthur was the noble ruler of Equestria, husband of Princess Celestia, father of Prince Soulander and Princess Shine, and one of Equestria's greatest heroes.
Two thousand years ago, after Discord was overthrown, the newly-emerged-Princess Celestia fell in love with the wifeless lonely Arthur, who was once an ordinary unicorn. Little did she know that Arthur did the same thing. Eventually, Arthur and Celestia were married in front of the whole kingdom. As a result, Arthur emerged as the new King of Equestria and transformed into a powerful alicorn like his spouse.
Several years later, Princess Celestia gave birth to an alicorn foal named Prince Soulander. The son of Arthur grew up to be a noble prince and a hero like his father.
But, as Soulander grew up into a full-grown alicorn, he changed. Although he had everything his heart desired, the prince was spoiled, selfish, and unkind. He mistreated most of his friends, servants, workers and knights brutally and cruelly. King Arthur did not tolerate such behavior his son possessed. Therefore, he removed Soulander's honor to becoming prince for it to be passed on to his future daughter.
Prince Soulander became shrouded in pure anger. He threw away the good in him and through arrogance, created dark magic, which is made from the aggressive feelings of hatred and anger. In his desires to rule Equestria with an iron hoof, Prince Soulander became the Black Cross King and waged a great civil war against his own parents. The civil war took place when Soulander was 300 years old. However, in the Battle of Canterlot, King Arthur challenged the Black Cross King in a personal bloody combat. Arthur managed to seal his own son away in Tartarus, but not before the Black Cross King wounded his father mortally, causing him to bleed to death with every hour passing. King Arthur died protecting Equestria and ending the civil war with his victory.
Over 1,300 years passed since the imprisonment of the Black Cross King, Celestia gave birth to another child, named Princess Shine. Though she was born from the Princess of the Sun herself, she was fatherless because Celestia's spouse King Arthur died long before Princess Shine was born. She was given the title "Princess of Color" and the privilege to co-rule Equestria with her mother. Today, little did Princess Shine know that her father was actually the once-great King Arthur.
Name: King Arthur
Age: 600 (as of 537 C.E.)
Birthdate: 63 B.C.
Death: 537 C.E.
Coat color: Golden
Eye color: Purple
Mane and tail color: Brown-and-orange
Aura color: Yellow (middle horn), Red (left horn), Blue (right horn)
Cutie Mark: A golden crown on a sun with a moon with a dark-blue sky at the sun's center (symbolizes King Arthur's authority over Equestria)
Relations: Princess Celestia (wife)
Prince Soulander / Black Cross King (son)
Princess Shine (daughter)
King Sombra (grandson)
Sir Bedivere the Colt (brother)
Princess Luna (sister-in-law)
Princess Cadance (niece)
Prince Blueblood (nephew)
Twilight Sparkle (niece-in-law)
Shining Armor (nephew-in-law)
Position: The King of Equestria
Occupation: Leader, King, Ruler