From Fake Dreams

My body is made of blades… Fire is my blood… and Glass is my heart… Through countless battles I forever wait, alone on the hill of blades… For Hell's hands to bear… For Heaven's hands to temper…
Emiya Shirou

In the aftermath of the Fourth Holy Grail War, Emiya Kiritsugu was content to live out his final days with his newly adopted son Shirou. However, he found himself beset by strange dreams, dreams that told him the results of his incomplete training of Shirou's magecraft. As a result, he knew that he had to prepare for the future. For a Holy Grail War that was approaching fifty years early.

From Fake Dreams is a Fate/stay night Alternate Universe Fic written by Third Fang, author of the incredibly long Yet again, with a little extra help Fanfic. The story follows the Magus Killer as he seeks to have Shirou properly trained in skills for the upcoming war, and then Shirou as he tries to make sense of the world of Magi he's been thrust deep into.

Tropes used in From Fake Dreams include:

Accidental Innuendo: In-Universe, with Shirou delivering a ridiculous amount in Chapter 15. Bazett and Rin can't help but notice, though.
- Even his Pre-Mortem One-Liner is not immune.
Ambiguous Disorder: Shirou, who doesn't seem to realize that Rin has feelings for him and consistently takes her at her word. This causes… a little friction. Being "distorted" (as in canon), this is unsurprising.
Arson, Murder, and Jaywalking: The King of Rats in chapter 17 when the others are noting the fact that he is an unusually well mannered demon.
- The King of Rats smiled. "You are not the first to say that young girl. My master himself was also quite intrigued when he first realized that I am rather fond of the human race even though he did not create me as such." He raised the mace to the light in the room to get a better look at it. "When he asked me about it, I merely replied that I constantly work for the betterment of all rats, my master… and humans so long as the latter continue to make pizza of course."
Badass Creed: Not finished yet, but he's close to Unlimited Blade Works:

My body is made of blades… Fire is my blood… and Glass is my heart… Through countless battles I forever wait, alone on the hill of blades… For Hell's hands to bear… For Heaven's hands to temper…

Badass Teacher: Kuzuki has been sparring with Shirou.
Big Bad Ensemble: Louvre, Zouken Matou, Kirei Kotomine, & Gilgamesh. For now, anyway...
- Well... we can declare without doubt that Louvre is Deader Than Dead as of chapter 16.
Black Swords Are Better: Shirou's most dangerous sword Kiritsugu is a black longsword with blood-red stains and brown veins on it.
Blasting It Out of Their Hands: Rin does this to Louvre, to multiple characters' surprise.

"…I can't believe that actually worked…" Rin, Bazett, Shirou, and Waver muttered under their breaths in relief and or mild disbelief.

Chekhov's Gun: Shirou's inherited magic crest ends up being a Game Breaker against Louvre: Time magic, combined with the Origin Sword Maiya, equals a way to bind a vampire's personal timespace to the Gaian timeline, thus nullifying his pesky healing factor. I repeat: Shirou is now not only a major threat to magi all around, but it expands to magi-turned-Dead Apostles as well.
Cool Swords: The Origin Swords are Game Breaker material, to be blunt, to the point that Shirou could easily become The Dreaded for other Magi. Bazett has told him upfront that she'd kill him if he ever made her list before he could use them.
- Natalia: Can cut through anything with magic resistance lower than C+ rank – B rank, if it's a living thing – if he even so much as touches them with it. Otherwise, it's an Absurdly Sharp Sword.
- Maiya: Can bind things, including alterations and souls, improperly, effectively screwing over anything that can split itself apart or adding something to their very core.
- Kiritsugu: This blade… well, it Severs and Binds just like the Origin Bullets, but combined with the curse… it hits them down to the very soul. Hitting someone's magic with it can cause them to literally lose the memory of the spell. If it hits them directly… Well, let's just say even Roa wouldn't be able to escape it. Louvre found out just how terrifying it is, the hard way.

Shirou: Sacrifice and save, blade of the cursed hero. Kiritsugu!

Dark Is Not Evil: Shirou's swords may turn out to be this.
Didn't See That Coming: Waver Velvet's plan to rescue Sirius runs afoul when Louvre uses his newly-acquired weapon.
- Shirou is offered both a scholarship under the Queen and the role of the 10th Dead Apostle Ancestor.
  - The Queen seeks to use him as a public enforcer for this reason and gave him a Noble Color for his advancements.
Dead Man Writing: Kiritsugu left behind letters to be read by Shirou once the the fifth Heaven's Feel goes into swing. Recent circumstances, however, led to Shirou discovering the letters early, although only one has revealed its contents.
Deader Than Dead: The final fate of anything hit by the Origin Blade Kiritsugu. The souls can't even go through Reincarnation!
Death by Adaptation: Shinji bites it after running into Louvre's son. Not that anyone actually complained…
Deal with the Devil: Shirou is forced into one with Zouken regarding the war and Sakura.
Dreaming of Things to Come: Basically what kicks off the entire story. Kiritsugu basically sees all three routes, the Multiple Endings, Bad Ends (sans Tiger Dojo), and the life of the Shirou that became a Counter Guardian.
Flaming Sword: Louvre's son has one with blue flame that drains od on contact.
For Want of a Nail
I Am Not My Father: Shirou insists it is not his intent to become like his father, despite how he has the potential to become the next Magus Killer.
Indirect Kiss: Rin didn't realize she was feeding a still-recovering Shirou using the same chopsticks she was eating with until Sakura pointed it out to her.
Instant Runes: Sirius' greatest Mystic Code, the Lebor na nUidre, the Book of the Dun Cow, is actually his skin, and allows him to instantly create runes on any part of his body, enabling him to give himself a wide range of abilities. It also allows him to make said runes on the outside world significantly faster than most magi. And also earned him a Sealing Designation, unfortunately. Fortunately, the milder variation. And he was prepared for the eventuality.
My Death Is Only the Beginning: Part of Kiritsugu's plan includes making Origin Swords from his bones for Shirou, which only occurs after his death.
Mundane Utility: Shirou can, thanks to his utterly broken Reinforcement, make any type of jewel he desires, provided he has the neccessary materials beforehand. As Rin finds out in chapter 17.
Named Weapons: The two curved blades of Severing and Binding were named Natalia and Maiya respectively, while the longsword that contains both Origins was named after Kiritsugu himself.
- Meaningful Name: Like Kiritsugu himself, the name reflects both Origins: Severing ("kiri") and Binding ("tsugu").
Names to Run Away From Really Fast: The Ash of Miracles. Guess who.
Not What It Looks Like: When Shirou is returning a prana-filled jewel to Rin, Taiga thinks Shirou got himself a new girlfriend.
Naughty Tentacles: According to Bazett, every female enforcer has to deal with them at least once.
Original Character: Sirius McGinty, crafter of Mystic Codes, including Kiritsugu's Thompson Contender.
- Chapter 18 introduces Marjatta Edelfelt, the younger sister of Luviagetta Edelfelt, who due to the Ore scales aka Sisters characteristic of the Edelfelt clan is co-heir.
Poor Communication Kills: When the Tsundere nature of Rin clashes with "just want to be helpful to anyone" nature of Shirou. Shirou doesn't even know what he did wrong when Rin cuts off all contact for some time.
- Which Rin is forced to realize when she learns of his Reality Marble.
Posthumous Character: Kiritsugu is dead after 3 years of raising Shirou, by the end of Chapter 5.
Pre-Ass-Kicking One-Liner: Rin as she points the Thompson Contender at an enraged Louvre.

"…Get off my property."

Pre-Mortem One-Liner: In the same chapter as the aforementioned Pre-Ass-Kicking One-Liner, from Shirou when he's comparing Louvre's collection of weapons to his.

"It's not big enough."

Small Role, Big Impact: Kiritsugu dies even sooner than in canon due to giving Shirou his magic circuits, but his actions here set the new plot entirely into swing.
Spanner in the Works: Louvre, whose desire for Mystic Codes and Conceptual Weapons has him kidnapping Sirius. This leads to the chain of events that exposes the existence of Shirou and his abilities to not only the Mage's Association, but to Kotomine, Zouken, and Gilgamesh as well.
Storm of Blades: Like his canon counterpart, Shirou is completely capable of this. Taken Up to Eleven during his fight with Louvre, when he traces practically his whole arsenal simultaneously.
Soul Cutting Blade: Kiritsugu's intended function was to cripple a magus' magic circuits, but when that effect is reinforced by the curse of Angra Mainyu, the effect goes far further, all the way down to the very soul.
There Is No Kill Like Overkill: Shirou skewering Louvre with his entire arsenal of weapons, an arsenal whose count measures in the hundreds, if not thousands.
Too Much Information: Sirius in chapter 18 much to Bazett and Shirou's consternation.
What the Hell, Hero?: After Bazett saves Shirou by killing Louvre's daughter, she pretty much says this in regards to him making a Geas with Louvre's son in order to protect Rin and Sakura.
You Are Not Alone: Part of Rin's comforting speech when Shirou tries to make sense of receiving Mystic Code swords from Kiritsugu while being told to tone down his heroic-obsessed distortion.