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.

The "Fate/Unpublished Material" and "Fate/Side Material" booklets reveal an unused character for Fate/Stay Night.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.

Tsukihime, Fate/Stay Night, and Fate/Hollow Ataraxia were originally released as eroge games with hentai scenes in certain story routes. While the sex scenes in Tsukihime have little impact on the plot beyond building character relationships, the Fate games tied it in more by establishing sex as a means to transfer mana between two people. Years before their release, creator and writer Kinoko Nasu revealed frustrations at his previous job before co-founding Type-Moon with illustrator Takashi Takeuchi. He felt his producer's expectation of including obligatory H-scenes had "no understanding on a conceptual level" and resulted in H-scenes with no "passion". While he had no issue writing "normal" H-scenes, he found it difficult to write H-scenes with "a heavy emphasis on its plot" and keep them consistent with it. His solution to these qualms at Type-Moon when working on Tsukihime was to let Takeuchi come up with ideas and dialogue direction for H-scenes, and then fill in the blanks in the story.

This approach carried over to the Fate games, where they took a bolder public stance in their marketing. Around F/HA's release in 2005, Nasu insisted that certain story routes were "based around having porn", while Takeuchi commented that they wanted to use it as a vehicle for freedom of expression by telling a well-written story that could appeal to people beyond the H-scenes. However, starting with the expanded PlayStation 2 version of F/SN in 2007, almost all of the sexual scenes and plot elements in the Fate games (and at different periods Tsukihime) were either removed or rewritten in future releases, remakes, and anime/manga adaptations. Nasu felt the PS2 version of F/SN was the final version at the time due to its other improvements over the original version, and later clarified that he did not have "any objections to the presence or absence of sexual content if it fits the needs of the story". While the original eroge version of Tsukihime has not been re-released in recent years, Type-Moon re-printed the original eroge versions of the Fate games as a bundle in 2014 and 2019.

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.