The "Fate/Unpublished Material" and "Fate/Side Material" booklets reveal an unused character for Fate/Stay Night. "Tachie", otherwise known as "Galahad", "Shielder", or "Stray Servant" was planned as an alternate Heroine Servant the player could have chosen instead of Saber. She was scrapped from the game as to keep the story manageable.

This character was also planned for the animated adaptation of Fate/Stay Night by Studio Deen, but was scrapped in favor of an adaptation of the "Fate" Route. An animated movie featuring Tachie was also considered, but also abandoned.

This unused character was later revisited and inspired the design for Mash Kyrielight, a seperate Shielder Servant and primary heroine of Fate/Grand Order.

In Kinoko Nasu's first draft of Fate/stay night that he wrote while in high school, he had planned for Saber to be a man and the player character to be a woman in glasses. While the two genders were eventually flipped for the final game, this idea was revisited in "Fate/Prototype", an original video animation released as part of the Carnival Phantasm OVA collection. Fate/Prototype portrays Saber and the primary Master as described in the early drafts, but as of now, the full story of "Fate/Prototype" has yet to be told, with the animation and short story details being the only known aspects of this particular adaptation.

In a 2006 interview with Dengeki Online, lead writer Kinoko Nasu and character designer Takashi Takeuchi noted that they were never fully satisfied with the original PC release of Fate Stay/Night, considering it only 95% complete. However, rather than their beliefs stemming from the inability to add content, the pair stated that their main issue was that they didn't remove enough, with Takauchi calling the PC version cluttered and overlong. Consequently, a major challenge during the development of the PlayStation 2 port, Fate/Stay Night: Réalta Nua, was striking an ideal balance between streamlining the game and adding in additional material to incentivize purchasing it over the PC version.