Eventually, the Beautiful Assassin will use King Hassan's Noble Phantasm, Azrael.
- Maybe it will be her final attack before she is killed, or she will finish off one of the villains with it, perhaps Jester Karture. Either way, if it happens, it will be epic.
Flat Escardos will have some sort of link to Saint-Germain.
- Perhaps Flat could have a link to Saint-Germain—either Saint-Germain being Flat's distant ancestor or even a similar scenario with Shirou & EMIYA. They both are rather eccentric, have a fondness for steampunk (Flat specifically having Jack be a watch because he liked its design; as for Saint-Germain, well. Look at him), both also have a mysterious focus in regards to their eyes (Zugzwang & Ayaka both felt 'fear' in regards to their eyes). Coincidentally, in FSF, Saint-Germain also met with Iskandar which ties in nicely if it was indeed foreshadowing. Whether it's true or not, it's a fun theory.
Saint-Germain isn't lying about not being a time-traveller.
- Rather, there's something much more convoluted going on, like him having an EX Clairvoyance powerful enough to observe the whole timeline.
The Beautiful Assassin and True Archer will get an epic battle.
- She is ultra religious and he absolutely hates anything to do with the gods. They are bound to clash.
If True Archer uses King's Order: The Fifth Labor, it will make a flood.
- In the Fifth Labor, Heracles diverted two rivers to wash out the Augean Stables. Since True Archer doesn't care about innocent lives, he might use this to try to take out enemy Masters and potentially kill a lot of people.
- Confirmed in volume 8, where he uses it to fight Gugalanna.
True Assassin is Hassan of Meditative Sensitivity.
- Near the end of volume 2, the Beautiful Assassin's Zabaniya are analyzed, and when she arrives at the last one, Meditative Sensitivity, she is confused because she knows it was used by a previous Hassan but no one knows the era of said Hassan. The Zabaniya itself is poorly explained but is about sensing the flow of all sorts of energy as if it were part of her own body. In the following chapter, True Assassin is summoned, and his EX Presence Concealment is assimilating himself with the world. This feels too much like Foreshadowing.
- Confirmed in volume 8 to be True Assassin's Noble Phantasm.
Related to the above, True Assassin's true identity is the historical Rashid ad-Din Sinan.
- Outside of King Hassan, the Hassans Servants are usually pretty much an O.C. Stand-in (if not an outright Original Character if you're uncharitable) taking on the name of the historical Hasan-i Sabbah as Old Man of the Mountain, but there is reason to think that True Hassan is actually the second-most famous Hashshashin. One of his Skills is called Shadow Lantern, and in one famous anecdote about his life, on his way to assassinate Saladin himself, Rashid went down the hill of his fortress at Masyaf, who was besieged by Saladin's forces, and only his lantern was seen briefly before it disappeared completely among the tents. When Saladin woke up later, he saw a figure leaving the tent, all his lamps were displaced, and the would-be assassin left a note pinned by a poisoned dagger, threatening that he would be killed if he did not withdraw from his siege. And when True Assassin was summoned, he left Faldeus a message on a paper. Finally, the series mentions twice the Noodle Incident of Richard allying with Saladin and an Hassan to take down a Dead Apostle, and Rashid was contemporary to both Richard and Saladin, so it may very well come into play later, especially as, as of the seventh volume, an actual Dead Apostle is set on a path to potentially meet True Assassin.
- Jossed in volume 8. True Assassin's true identity is...weirder than that.
Richard will get the real Excalibur, or as close to it as it can get.
- When fighting Theia, Enkidu's Noble Phantasm Age of Babylonia is noted to be able to replicate even Excalibur, but it would need parts of world itself or treasures of equal value from Gilgamesh's treasury as ingredients to do so. Gil would pay the bill with a bunch of disposable NPs, Enkidu would forge Excalibur, and Richard be able to kill Gugalanna with a beam just as strong as the regular Excalibur beam.
The final battle will have everyone join together against Filia.
- She'll be trying to reacquire Ishtar's true power, and considering how powerful she actually is and her personality...
- While, by the seventh volume, the war's participants are en route to a "raid" on the Neo Ishtar Temple to stop her from regaining her full divine powers (which she is getting fast), and the Prelatis predict there are gonna be betrayals during it, it's unclear if Ishtar is truly the series' Final Boss.
Fillia is a mature body Illyasviel von Einzbern after the events of Fate/hollow ataraxia.
- Except Fillia is an Empty Shell and Illya isn't.
Tiné will eventually save Gilgamesh from his coma by feeding him the youth potion he gave her when they first met.
Ayaka is actually a Ruler-class Servant disguised as a human.
- It is made abundantly clear in the story that Ayaka is not a regular human, she possesses more Command Spells than normal which are scattered around her body rather than placed on her hand, can somehow supply mana to Servants despite not being a Mage, is essentially an outsider to both the False and True Grail Wars, and has no real stake or interest in seizing the Holy Grail. These are all hallmarks consistent with a Ruler-class Servant, albeit an incomplete one. In addition, Faldeus and the False Grail War organizers openly comment how it's highly unlikely for a Ruler to intervene in the False Grail War, and even if one does, they won't be able to do much about it. But considering how the entire War has completely spiraled out of their control, whose to say that a Ruler isn't already among the participants?
False Ayaka is actually an Albion Clone.
- We know that Thia thinks False Ayaka is a threat to the planet. It is heavily implied that whatever False Ayaka's situation is, it is caused by the three Mana Reactors owned/borrowed by Kayneth El-Melloi that were powering his "dimensional ghost maze" during Fate/Zero. When they exploded, the Semina Apartments were in the path of the fallout. Being mined from Tomb Albion; they came into contact with the original Ayaka and became a copy of her. Red Riding Hood is the result of the ghost program that Kayneth had it originally operating.
- This is similar to how in Lostbelt 6 of Fate/Grand Order; the Fairy Lord Aurora came into contact with a "claw" body part of Albion; and it became the fairy dragon Melusine. In fact, according to Melusine's Material; Melusine became a near exact copy of Aurora; with different colored hair and lacking Aurora's peculiar trait of growing into an adult.
- Maybe she's a Great Faery gone rogue? Thus she would have no shortage of mana.
Filia is going to come back at the worst possible moment
Filia is possessed by Ishtar, whose most famous myth is about them dying and then coming back from hell. And given the only reason they manifested is to make Gilgamesh and Enkidu pay and they hadn't succeeded by the time they were taken down, chance is they'll figure a way to come back - or Haruri will give their life to bring them back. The whole timeline is somehow artificially constructed
It was made a point in Nasuverse rules that Dead Apostle Ancestors and Servants cannot exist in the same world, and it is also noted that this world breaks the mold, being a cross between Tsuki and Fate timelines. Well, it'll turn that it is neither, but something else entirely, only made to resemble both on the surface. In other words, "strange fake" in the title refers to the whole world.