Yesterday, on the event, ufotable announced that will make anime for Fate/hollow ataraxia.

For those who don't know... Fate/hollow ataraxia is a visual novel game created by TYPE-MOON in 2005 which is the sequel to Fate/stay night. The word "ataraxia" in the title is a Greek term for "tranquility", giving the title the combined meaning of "empty (or false) tranquility".

The plot of Fate/hollow ataraxia is based 6 months after the events of Fate/stay night, taking place in Fuyuki City. The story, like Kagetsu Tohya, takes place in a dream world that reflects multiple timelines at once. It is a story that "encompasses the endings of all of the routes [of Fate/stay night], [while] not being any of them." It can be said not to follow any of the routes as a direct continuation, but rather act as a "counter" to the story of Fate/stay night itself. While "there is a setting about this happening after this route", it isn't that important and the player can interpret it either way. "Reopening" follows the ending of a "certain route" of Fate/stay night and the ending of Fate/hollow ataraxia. Even though hints towards the route exist, it is mainly left up to the readers' interpretation. While the scene "Sequel" depicts the world outside of the loop, it is unknown to which timeline it belongs as Kinoko Nasu said "It’s best if you don’t think too much about it" when questioned about its place in the timeline.