The Lancer (ランサー, Ransā?) Class Card of the Fifth Ainsworth Holy Grail War was summoned by Ainsworth Doll Kayneth El-Melloi Archibald in Fate/kaleid liner PRISMA☆ILLYA. It was later one of eight Class Cards transported to Illya's world.
The True Name of the Heroic Spirit of the Class Card is Cú Chulainn, one of the most famous heroes of Irish legend. He possessed a personality that was both cool-headed and aggressive, and he hid a brutal wildness.
Bazett Fraga McRemitz defeats the manifested Lancer before the start of the story. The Class Card is given to Luvia to help in her duties retrieving the rest of the cards, but it is used primarily by Miyu Edelfelt after Magical Sapphire decides to partner with her instead. Miyu utilizes it to defeat Rider with Gae Bolg, uses it to kill Caster while teamed up with Illya, and manages to take two lives from Berserker. Illya later installs it while fighting Kuro to gain experience in utilizing the Class Cards.
Lancer boasts great close combat ability and agility, and he also possesses some "Berserker Class characteristics." His primary Nobe Phantasm is Gae Bolg, a spear that carries the curse of cause-and-effect reversal. The true name being called makes it so that the result, "the heart is pierced", occurs first, and then the cause, "the spear is released", happens afterward. Agility cannot dodge the spear, but rather only high enough luck to evade the curse. Said to be a "one-hit, one-kill Noble Phantasm", it is very advantageous in singular combat.