Lancer is the class name of the heroic spirit Cú Chulainn, a legendary figure from Celtic mythology who is summoned as a Servant in the Fifth Holy Grail War of Fate/stay night. He is the son of the god of light Lugh and a mortal woman, which grants him high divinity and exceptional talent from birth. His childhood name was Setanta, and he earned the name Cú Chulainn, meaning the Hound of Culann, after killing the watchdog of the smith Culann and vowing to take its place. He later trained under Scáthach, the queen of the Land of Shadow, where he mastered combat techniques and received the cursed spear Gáe Bolg. In life, he was a famed warrior of the Red Branch in Ulster, known for his tragic fate and his tenacity in battle. As a Servant, he carries himself with the pride and dignity of a true hero, valuing loyalty and personal belief above all else. He is honest and straightforward, with a rough tongue but a genuine and earnest heart. He has a playful and carefree attitude toward life, often seeking out worthy opponents and enjoying conversation with friend and foe alike, but he becomes intense and serious in battle. He dislikes underhanded methods and betrayal, preferring direct, honorable combat. His primary motivation is the desire for thrilling, life-or-death battles against powerful heroes, and he has no particular wish for the Holy Grail, as he accepted his death in life. However, he is bound by duty to his Master and follows orders even when he complains, displaying a core of faithfulness. Due to a betrayal, his original Master Bazett Fraga McRemitz was killed by Kirei Kotomine, who used command spells to force Lancer into serving him. Kotomine orders him to fight but not to defeat his enemies, which prevents Lancer from using his full strength for most of the war. This constraint creates frustration for him but does not break his sense of duty. His role in the story varies by route, but he consistently acts as a formidable opponent or temporary ally. He engages in reconnaissance and combat, and he holds his own against powerful Servants such as Saber and even Gilgamesh for extended periods. In the Unlimited Blade Works route, he partners with Rin Tohsaka and Shirou Emiya to confront Archer and later, after being ordered to commit suicide by Kotomine, he refuses to die and kills Kotomine before burning down Einzbern Castle with rune magic. In the Heaven's Feel route, he is ambushed and killed by True Assassin, allowing the assassin to gain intelligence by consuming his heart. Key relationships include his turbulent and distrustful bond with his Master Kirei Kotomine, a rivalry with Saber that is marked by mutual respect despite differing ideals of honor, and a more cooperative relationship with Rin Tohsaka. He also has a notable history with Archer, against whom he fights a fierce duel. His development emerges through his struggle against the constraints placed on him and his ultimate acts of defiance against a Master he despises, revealing his unyielding will and fierce independence. He grows as a character by choosing his own path even when faced with death. In terms of abilities, Lancer is among the fastest Servants, with an agility ranking of A. He is a master of spear combat and is highly skilled in defense, possessing a set of abilities that make him extremely difficult to kill. His skill Battle Continuation at rank A allows him to keep fighting even after receiving fatal wounds, reflecting the legend of his death where he tied himself to a pillar to die standing. Protection from Arrows at rank B grants him the ability to evade any projectile weapon as long as he can see the shooter, including thrown Noble Phantasms, though it is less effective against wide-area attacks or long-reach weapons. He also has the Disengage skill, which allows him to retreat from battle and reset conditions to their initial state. He is proficient in rune magecraft, having learned the eighteen original runes from Scáthach, which he uses for tasks like searching, strengthening his parameters, and countering magical effects such as petrification. His most famous ability is his Noble Phantasm Gáe Bolg, which has two forms. The anti-unit version, Spear of Piercing Death Thorn, reverses cause and effect to guarantee that the spear pierces the opponent's heart once activated, making it nearly impossible to evade unless the target has exceptional luck or instinct. This ability uses little magical energy and is highly efficient. The anti-army version, Soaring Spear that Strikes with Death, is a full-power throw that scatters into a barrage of projectiles, unleashing massive destructive force over a wide area but requiring all of his magical energy. Overall, Lancer is a warrior defined by his raw combat strength, his unwavering spirit, and his sense of honor, yet he is ultimately a tragic figure whose potential is often curtailed by the circumstances of his summoning.