Fate/ninth heaven is, as you may guess, my version of this mad crossover. It plays out much like Fate/stay night does--five routes, all about sixteen days long, in which a protagonist makes a contract with a Servant and fights through the Grail War.
However, there are a few important differences.
Fate/ninth heaven takes place several years after Fate/stay night's third route, "Heaven's Feel". Therefore, this is the sixth Holy Grail War. Rather than starting in the same place and branching off due to the choices of the protagonist, the five routes are each told from the perspective of a different protagonist, and events play out a bit differently from the start.
A few warnings that readers may want to keep in mind:
-Fate/ninth heaven is intended for mature audiences, and future chapters will contain graphic violence and sexual material. The main pairings for each route (and there is only one for each route) are of all sexual orientations, so if this bothers you, you probably don't want to read it.
-For a comprehensive list of content warnings, please see the page for this series at Archive Of Our Own!
-Because this story takes place after Heaven's Feel, there will be spoilers for all of Fate/stay night, as well as possible spoilers for Fate/hollow ataraxia and Fate/Zero. (And, no, if you're just coming into this with knowledge of the anime alone you really don't know anything about Fate/stay night.)
-There will also be spoilers for Riviera, Yggdra Union, Knights in the Nightmare, Blaze Union, Gungnir, and Gloria Union.
-Concerning Knights in the Nightmare and Gungnir, I will be using Sting's Romanizations of character names because I personally prefer them over Atlus'.
-All routes but the first have multiple endings; the narrative itself will assume all best choices have been made, and progress towards the best endings. As for the other endings, I'll probably include them as side chapters after a route is complete. I don't know how I'm going to handle this in the third and fourth routes, where there's distinct branching towards the end depending on a certain character's affection value, but I'll handle it when I'm there I guess.
i. One day I
ii. One day II
iv. menage à trois
viii. Believe (I)
ix. ever cry,never life
xi. mirror image (part one, part two)
xiii. Believe (II)
xv. BLUE SKY
TRUE END - Warm Smile
i. One day III
vi. pure (I)
viii. folie à deux
ix. pure (II)
xii. Beloved (I)
xiv. violation (I)
xv. Beloved (II)
TRUE END - White Garden
GOOD END - Summer Rain
Vagrant Grail Cadenza
vi. too late? not late
vii. safe harbor
ix. anemone (part one, part two)
x. PENALTY at five (part one, part two)
xi. violation (II)
xiii. precious (part one, part two)
xiv. stigmata (part one, part two)
xvi. unlimited. (part one, part two)
xvii. ARIA (high speed ver.)
NORMAL END - Silent Room
TRUE END - Sunrise on the Water
GOOD END - glitter days
i. One day IV
ii. glass slipper
iv. Babel (I)
Resplendent Thousand Petals