Sakata Gintoki is a samurai living in an era when samurai are no longer needed. He is recognized by his natural curly hair and sweet tooth. He often blames his "perm" hair of sorts to be a source of some of his misfortune. Gintoki lives with Kagura and Shinpachi, taking on odd jobs to make the world a better place and to pay their rent. In the Joi war, he was known as the "White Demon" due to his silver hair and white coat he wore in battle, which, combined with his impressive capabilities as a swordsman, made him famous among his comrades and struck fear into Amanto.

He is the Servant of one of the series' main heroines, Rin Tōsaka. Due to an incomplete summon, he apparently has no memory of his previous life or identity. Archer is sarcastic and cynical - but under his hardened exterior lies a complex and dark personality that unfolds throughout the story. Though skilled with ranged weapons, he can hold his own in melee combat. Archer considers Shirō Emiya's idealism to be weak and delusional, recognizing Shirō's mentality of "wanting to save everyone" as naive and impossible.