Shirou Emiya , also written as "Shiro Emiya" in Fate/unlimited codes, is a fictional character and the main protagonist of the 2004 visual novel Fate/stay night, published by Type-Moon. Shirou is a teenager who accidentally participates in the "Holy Grail War" alongside six other mages looking for the eponymous treasure, an all-powerful, wish-granting relic. Shirou was the sole survivor of a fire in a city and was saved by a man named Kiritsugu Emiya who inspired him to become a hero and avoid killing people during fights. While fighting alongside the servant Saber, Shirou develops his own magical skills and, depending on the player's choices; he forms relationships with the novel's other characters. He also appears in the visual novel sequel Fate/hollow ataraxia, the prequel light novel Fate/Zero, and printed and animated adaptations of the original game.

Fate/stay night is a Japanese visual novel game developed by Type-Moon for Windows on January 30, 2004. Initially released as an adult game, a version titled Fate/stay night Réalta Nua, which replaced the sexual content with extensive visual and narrative elements, completed the story with an ending scene, and featured voice actors from the 2006 anime series, was released on April 19, 2007 for the PlayStation 2. It was later ported to Windows in 2011, PlayStation Vita in 2012, and iOS and Android in 2015. A remastered version of Réalta Nua is set to release for Nintendo Switch and PC via Steam in 2024, marking the first time the game will be available outside Japan. The plot focuses on a young mage named Shirou Emiya who becomes a warrior in a battle between "Servants" known as the Holy Grail War. Shirou bonds with a heroine through each route and confronts different adversaries participating in the war. The author, Kinoko Nasu, summarised Fate/stay night as:"...the story about legendary heroes and 'a boy meets a girl.'... The main theme is 'conquering oneself.' There are three story lines in Fate, each has a different themes. The first one is the 'oneself as an ideal.' The second one is 'struggling with oneself as an ideal.' The third one is 'the friction with real and ideal.' This game is describing the growth of the main character Emiya Shirou. The first storyline shows his slanted mind, the next storyline shows his resolve, and the last storyline gives another resolution for him as a human. All three storylines are essentially equal, but they have different forms."