Lancer, the Irish mythological hero Cu Chulainn manifested as a Servant, exists in an alternate timeline where the Fifth Holy Grail War concluded without bloodshed. He maintains amicable ties with Shirou Emiya, frequently joining meals at the Emiya residence alongside other former war participants. Though his arrivals occasionally spark brief tension—particularly with Saber—the mood invariably shifts toward camaraderie during shared dining.

Residing in Fuyuki City, he works a part-time job to engage with humans in mundane contexts. His cheerful, boisterous personality surfaces during errands for ingredients or lively enjoyment of food and alcohol. Unintentional physical comedy arises from his supernatural strength, like overzealous back pats that stagger Shirou or misjudged force launching a charging boar skyward.

He dives enthusiastically into group activities, including a spirited volleyball match against Shirou and Saber where rivalry stays playful. His effortless charm shines when he captivates Ayako Mitsuzuri with a casual compliment and offered flower. During festive gatherings like Christmas at Illyasviel von Einzbern’s castle, he amplifies the celebratory atmosphere. Though Servants require no sustenance, he relishes well-cooked meals alongside others.

In the Nintendo Switch game *Everyday♪ Today's Menu for the Emiya Family*, he debuted as a playable character via the "Lancer Scenario Pack" DLC released August 5th in Japan, featuring his unique cooking scenario and original menu.