Sir Kay

About

Unknown class Servant summoned by Goddess Rhongomyniad in the Grand Orders of Fate/Grand Order.


He appears in Lord El-Melloi II Case Files as a spiritual being that exists within Gray's Mystic Code Add.

Kay was the son of Sir Ector and foster brother of Artoria, who later became known as King Arthur. Due to being female, Artoria could not inherit the throne by normal means, so she was given to Ector by Merlin to be raised as a simple knight apprentice at the age of five. Although Kay could tell she would grow up to be a beauty, his father told him to guide her like she was his brother. Deciding to treat her in that manner, he did not believe it would be kept secret. Artoria was initially raised under the belief that they were related by blood, but she was later told the truth while growing up. Their relationship did not diminish from the truth, and they still felt they were true siblings. Her identity as being female was known to him, but he kept the secret all his life after being sworn to secrecy by Merlin. Artoria acted as his attendant, carrying their weapons and provisions on outings, and she trained with both Kay and Ector in the ways of combat and the ways of being a knight. They often trained with wooden swords, and although Artoria was superior, she never once defeated him. Despite her always having been victorious in combat, they always argued while they fought, and due to Kay's arguments, she always felt like she had lost against him.


After Artoria died, Kay's corpse was brought along with her corpse and her holy spear Rhongomyniad to Blackmore Cemetery. Morgan le Fay created the Mystic Code Add to seal Rhongomyniad and keep it from losing its Mystery. Morgan chose Kay as the base for Add's pseudo-personality because of all the Knights of the Round Table he was the one who had the least admiration for King Arthur. This was done without Kay's consent.

(Source: Type-Moon Wiki)