Saber's True Name is Gawain (ガウェイン, Gawein?), one of the Knights of the Round Table that appeared in the Arthurian legends, also known as the White Knight of the Round Table (円卓の白騎士, Entaku no Shirokishi?).
If King Arthur was the night, the symbol of the moon itself, then Sir Gawain was the day, which shoulders the sun. He acted as King Arthur's impersonator (in the kagemusha sense) in the royal castle of Camelot. In other words, he was one of the candidates to substitute the King after his fall. He is the bearer of the sister-sword to Excalibur, Excalibur Galatine. However, in his blind adoration for the King, he remained unaware of the King's agony. A loyal knight just like Sir Bedivere who took care of King Arthur in his final moments, but unlike Bedivere who wished for the King to attain happiness as a person from the bottom of his heart, Gawain wished for him to flourish as a king. Unmindful of such evaluation and intentions from those who surrounded him, Sir Gawain remained as King Arthur's right-hand to the end.
He never looked down on his enemies. Needless to say, he also never insults his enemies, confronting them with politeness and maintaining his fighting spirit and resolve even when the opponent lacks capacity. Remaining under the shadow of the King, he gallantly proceeds to the battlefield once the command is given and triumphs with a refreshing smile. Naturally, he was described as the ideal knight. His greatest regret was his dispute with Sir Lancelot. He was a knight who was equal to Sir Lancelot but was also incompatible with him, unable to forget that Lancelot killed his brothers, Gareth and Gaheris. With a pure personality, he was an ideal young warrior and thus his affection towards his relatives was greater than in others.
"Sir Lancelot not only killed my brothers, that black knight even betrayed the King. Kidnapped the King's wife. How expect that to be forgiven?" —Gawain
But in the end, King Arthur forgave Sir Lancelot; "I was at fault for everything". Gawain, however, never forgave Sir Lancelot's betrayal and remained hostile towards him to the end. That grudge not only cost Sir Gawain's status as a knight, but in the end even played a part in the King's ruin. Sir Gawain continued to reject Sir Lancelot when he attempted to participate in the Battle of Camlann even after being excommunicated and, consequentially, caused the death of both the King and himself.
During King Arthur's final battle at the hill of Camlann, Sir Gawain died after being struck by Mordred in an old wound inflicted by Sir Lancelot. Just as King Arthur reproached himself in the hill of Camlann, Sir Gawain, too, cried in his deathbed. His passion invited the King to death. He regretted that his grudge invited the ruin of the King and accepted his enmity towards Sir Lancelot - and even Lancelot's disloyalty - as coming from his own lack of virtue. Although his ending that did not help the king in the legend, that loyalty was sincere to the very end.
"...in the chance there is a next time. If there is an opportunity to restore my honor - a second life - then at that time I will devote my everything to the king..." —Gawain
Thus, he was brought back as a Heroic Spirit. From this conclusion, the Heroic Spirit Gawain seems to perceive "being of assistance to the king" as his absolute mission. Now set free from all doubts, Sir Gawain regained his proper figure as a literal Knight of the Sun (太陽の騎士, Taiyō no Kishi?). Having become a Servant while retaining such an oath in his heart in order to correct his mistake, the regret of his past life, Sir Gawain serves his Master as an even more perfect "knight". All for the sake of becoming the cornerstone of a single, lonely king.
Gawain wanted to serve a true king loyally without questions or doubt like a true knight. The relationship between Leonardo B. Harwey and Gawain is like a real brother watching the growth of the younger brother. However Gawain saw flaws in his master and he understood that his master lacked the experience of defeat. Gawain didn't tell him because he wanted to witness his master's growth before his defeat. He can be overly protective to Leo and insults Hakuno's Servant, for example he calls Saber as Whore of Babylon (バビロンの妖婦士, Babiron no Yōfushi?), threatening Caster to "Step back, you foul demon woman" (「下がれ下郎、魔性の女。」, "Sagare gerō, mashō no on'na"?) and Archer as unskillfulness (不器用, bukiyō?).
He built a good working relationship with Julius B. Harwey and he describes Julius similar to Lancelot.
He believes that quantity is over quality when it comes to food. He is satisfied with large quantities of potatoes, vinegar, bread, ale and vegetables.
In Fate/Extra, he was summoned by Leonardo B. Harwey as a Saber-class Servant. Leonardo refers him by his real name to intimidate others. Gawain would follow Leonardo like a shadow and serve him like he would a king.
In the Sound Drama, Gawain defeated Lancer with a single blow of his sword, Excalibur Galatine.
He was the last Servant in school that Hakuno would face. Depending on Hakuno's Servants, Gawain would interact them differently. With his defeat, Leonardo finally learns of defeat and thanked Gawain for his services. He pointed out to Leonardo that he was honored to witness an honorable king before fading out.
While BB devoured both Masters and servants, Leo was able to retain Gawain as his servant. In the majority of the game, he assisted Leo in the student council.
In Chapter 1, when Rin demands money for Hakuno Kishinami to pass through her programs, they can borrow money from Leo. Gawain will travel to the Sakura Labyrinth to find Hakuno and ask them to return the money. If Hakuno doesn't return the money by selecting the second option, a battle between two Servant would start. If Gawain wins, he'll reclaim the 100000sm from Hakuno and the opposite if Hakuno wins.
After Hakuno defeats Karna and Jinako Karigiri, Leo and Gawain take action in Chapter Bad End. Leo activates his Sword Camelot codecast skill to create a fire wall to take on BB by himself. Leo and Gawain challenge BB but Gawain and Leo suffer a massive defeat. When BB attempts to absorb Gawain, Leo uses all three of his Command Spells to make it so that he and Gawain had already broken their contract before BB's interference with the Holy Grail War.
Fate/Extra CCC Foxtail
His role is similar in CCC. When Meltlilith and Passionlip invaded the school, Gawain intercepted them. When the fight appears at a disadvantage, Karna helps Gawain. They teamed up and cut down Passionlip.
He was briefly mentioned in the original novel of Fate/Zero when Saber fought against Berserker. As Berserker revealed his true identity, Saber was tormented on how she led her kingdom. She thought of her knights and wondered if they had left this world with resentment and unwillingness. Saber claims that Gawain had heroically sacrificed himself.
Although he doesn't appear in Capsule Servant game but within the world of Capsule Servant, Gawain is the father of Master Artoria, Lancelot, Kay and Bedivere.
It is said that Gawain is possibly a greater Heroic Spirit than King Arthur during midday when the sun is at its highest. Gawain is an extremely skilled swordsman who wields Excalibur Galatine, a sister-blade of Excalibur gifted by an Elemental called the Lady of the Lake. Though not as famous as Excalibur, it possesses power that could rival the legendary sword. Galatine has a fragment of the sun dwelling inside it, said to be able to purge evil. Gawain says that the sword is the incarnation of the sun itself.
- Protection of the Fairies (精霊の加護, Seirei no Kago?, localized as "Divine Aegis") to boost his Luck, the effect would only last for 3 turns. He will use this skill on the 2nd move.
- Siege Perilous (円卓の刻印, Entaku no Kokuin?) to boost his defense, it seals enemy Skills when using GUARD. The effect would only last for 3 turns. He will use this skill on the 5th move.
- Blade of the Devoted (忠義の剣閃, Chūgi no Kensen?), a powerful strike with Excalibur Galatine. He will use this skill on the 3rd move.
Compared to King Arthur's providence from the moon (Artemis, the pedigree of goddess of the moon), Sir Gawain is the knight who receives grace from the sun earning him the title of "Knight of the Sun". This skill, Numeral of the Saint (聖者の数字, Seija no Sūji?) power is displayed at its maximum at noon when the sun is at its highest. During the hours between 9am and 12pm and those between 3pm and sunset, all of his powers increase by a factor of three. This was related to the ancient belief that numeral "3" was the sacred number of the Celtic deities. In the game, the player couldn't damage him due to this ability until steps were taken to circumvent or negate it. In battle he can still use this skill but to a certain degree, he'll activate it when his HP is below 10%. It greatly reduces the damage done by enemy attacks. The effect would only last for 1 turn. He will use this skill on the 4th move.