After resolving the Incineration of the Human Order, Chaldea suddenly detects a singularity in Shinjuku, Tokyo, 1999 AD. With the protagonist as the only Master on call, da Vinci decides to go ahead and let them Rayshift there to save the world one more time. Unfortunately, a magic barrier interferes with their entry and they end up in free fall above the cityscape before a mysterious man saves them...
Road Raging Monster
Black Maiden Fire Wheel
The Great Prison Break
Great Detective Work
Return of the Wolf King
Shinjuku Fly High
Barrel Tower Battle
Great Detectives' Great Deduction
- Card-Carrying Villain: Moriaty proudly describes himself as this, his plan to destroy the world is both an attempt to beat Holmes for once and just to see if he truly can destroy the world.
- Crossdresser: Either the protagonist is Disguised in Drag or Sweet Polly Oliver at a formal party they sneak their way into, depending on which gender you picked. The trailer shows that the female protagonist wears the "Fate/Accel Zero Order" Mystic Code but the male protagonist's dress is never shown on-screen.
- Cool Old Guy: Moriarty despite being one of the most famous arch-enemies in fiction, is laid back and hilarious when he's lost his memories even if he still has his ruthless streak.
- The Dark Side Will Make You Forget: Lobo muses as he's dying that because he was so driven by his hatred of humanity, he can no longer remember his home, the Currumpaw plains instead now the corrupted Shinjuku is his home.
- Debut Queue: Emiya Alter is added to the summoning gacha after completing the episode.
- The Dreaded: Everyone is horrified by Hessian Lobo with his bark being seen as an universal sign in Shinjuku to run.
- Everybody Lives: Surprisingly, despite the darker direction all of the Servant allies live to the end of the Singularity. The only "exception" is Moriarty himself, who was one of the real villains and using a Memory Gambit and needs to be put down.
- Gameplay and Story Segregation: Mash joins the Mission Control staff because she lost her powers as a Servant, but she is still playable in-game.
- Headless Horseman: The Headless Horseman shows up, though it's too weak as an urban legend to become a full-fledged Servant and needs Lobo to become a Servant. The party initially thinks that it is in control as a Rider but it's later revealed that Lobo is in control, even before they become an Avenger.
- Heroes Love Dogs: To soften Altria Alter, she's shown to have adopted an adorable white dog in Shinjuku, even naming it and is very defensive of him.
- Home Base: Saber Alter temporarily sets up shop in the basement of a fast food chain restaurant and it serves as Chaldea's base of operations for the protagonist and their Servants in Shinjuku.
- Memory Gambit: Moriarty loses his memories on purpose as part of his and Baal's scheme, one genuinely friendly but amnesiac who serves as a major ally, and one entirely ruthless who plays the role of main villain. They both sealed their memories so that they could act out their roles perfectly, so that Moriarty could get close to both Holmes and the protagonist, the former so that he could backstab Holmes when he least expected it, and the latter so that the 7th bullet of Der Freischütz, which targets the person most important to him, would target the protagonist. This naturally backfires when Moriarty finds he doesn't have the stomach to harm someone he genuinely cares about.
- Mission Control: Mash is demoted to this because the loss of her powers makes it too dangerous for her to go out in the field.
- Out-of-Character Alert: Edmond Dantes naming himself as such, tips off the protagonist that its an imposter, since Dantes never refers to himself by name instead calling himself the Cavern King.
- Significant Wardrobe Shift: Jeanne Alter reveals that she can just casually change clothes whenever she feels like it and this is the first time Servants start wearing outfits besides their three ascension forms.
- Sitcom Arch-Nemesis: Altria Alter and Jeanne Alter's rivalry returns but they tone it down because of the protagonist. While they would be happy to murder each other, they instead just take every chance to mocking each other.
- Theory of Narrative Causality: Moriarty can't defeat Holmes conventionally because the narrative logic of Doyle's stories dictate that he will always be outwitted by the end. Due to this, his plan to avoid that has him fully assimilate into the party as one of the good guys and to backstab Holmes when he thinks the story has been resolved.
- Urban Fantasy: Notably the one time Grand Order dips into this territory thus far with Servants duking it out at late night and a magical criminal conspiracy taking control of the city.