Kayneth El-Melloi Archibald

Kayneth Archibald El-Melloi is a nobleman and a renowned mage from the Magus Association and a Euryphis lecturer with a magical lineage that gone back for nine generations. He is the Master of a Lancer class servant in the 4th Holy Grail War.

His magical abilities are attributed to wind and water and he is an expert who is proficient summoning, alchemy, and spiritual evocation. He is a teacher of Waver Velvet and, after reading Waver's radical thesis concerning increasing magical potential, tore up his student's manuscript. Waver, in retaliation, enters the fourth Holy Grail War with Kayneth's artifact and incites Kayneth's anger.

Lord El-Melloi is a cruel man who prefers to attack his opponents from a safe distance from the safety of his strong hold in the Fuyuki Hyatt Hotel. Kiritsugu Emiya initially regards Kayneth as one of the two most threatening magi involved in the war.

He is engaged to Sola-Ui Nuada-Re Sophia-Ri, the daughter of the head of the spiritual evocation division, through an arranged marriage. They apparently do not get along and Sola-Ui considers Kayneth a coward for not going and attacking the opposing Masters face to face. While he loves her, she does not appear to share the same sentiments.

Role
Kayneth is the Master of Lancer in the Fourth Holy Grail War. His participation in the war is merely to increase his own prominence with the Magus Association. His base of operations at the Fuyuki Hyatt Hotel is on the hotel's thirty-second floor and protected by twenty-four layers of bounded barriers, a countless amount of summoned monsters, various traps, and mystical spatial alterations in the lobby.

After Lancer's battle with Saber, Kayneth criticizes his Servant for not attacking Saber with all his strength. He winds up arguing with Sola-Ui, who calls him a coward for hiding himself from the other Masters and criticizes him for his poor strategy and not thinking of having Lancer work with Saber to finish off Berserker. Though Lancer convinces her to stop arguing with Kayneth, her immediate submission to the Servant leads Kayneth to suspect Sola-Ui is developing affections for Lancer.

Before he can address the issue, the lower levels of hotel are attacked by Emiya Kiritsugu and Hisau Maiya. Kayneth and Sola-Ui interpret the attack as one of the Masters driving people out of the hotel in order to attack Kayneth without any civilian casualties getting in the way and anticipated how to counter accordingly, Kiritsugu and Maiya actually aim to destroy the hotel's foundation. Kayneth, Sola-Ui, and Lancer manage to survive the attack.

After the battle to defeat Caster, Kayneth approaches Kotomine Risei to obtain the command spell promised to the Master who manages to defeat Caster. After forcing the reluctant Risei to comply based on Kayneth's assertion of Lancer's role in defeating Caster, Kayneth shoots Risei to prevent the regulator of the war from giving out any more command spells. He discovers later that Sola-Ui was captured during the battle against Caster.

Though furious at Lancer, who was also unaware of Sola-Ui's capture, they are forced to fight against Saber and Irisviel von Einzbern. Watching the duel from a hidden location, Kiritsugu appears before Kayneith with Sola-Ui at gunpoint and offers a mage's contract, an absolute agreement which will render a mage permanently unable to perform sorcery if broken. Kiritsugu offers that Kayneth and Sola-Ui will not be harmed should Kayneth force Lancer to kill himself. After examining the contract to determine its authenticity and considering leaving the country with Sola-Ui alive, Kayneth agrees and orders Lancer to kill himself.

However, as soon afterwards, Kayneth and Sola-Ui are attacked by Maiya, armed with a machine gun. Kayneth survives the initial gunfire and begs that Kiritsugu end his pain; Kiritsugu refuses because of their contract. In the end, it is Saber, disgusted with her Master, who ends Kayneth's life by beheading him.

Servant
Kayneth originally intended to summon Iskander, but his artifact, the mantle of Alexander, had mistakenly been entrusted to his student Waver Velvet. Waver, who had gotten into a dispute with Kayneth, stole the artifact and summoned Rider.

In order to participate in the fourth Holy Grail War, Kayneth summoned Lancer-class servant Diarmuid Ua Duibhne. Through the modification of the Master-Servant system, Kayneth has devised a method to allow two simultaneous connections to Lancer; while he holds the command spells for Lancer, the energy to materialize the Servant is maintained by Sola-Ui.