Like the title implies, it is a For Want of a Nail story. The "nail" in question being that Waver steals a different relic delivered for the Holy Grail War from Kayneth. Instead of Iskander, Waver summons Diarmuid. The fic focuses primarily on the relationship between the young student and the Celtic knight.
However, that is not the only thing that is different in this Grail War. All of the Servants are switched around, making things even more unpredictable.
Updated last in early October 2020.
For Want Of A Relic contains examples of:
- Abandoned Area: Waver and Lancer's base of operations is a run-down and forgotten estate on the edge of the city. Better known in canon as the Emiya household.
- And I Must Scream: Kariya, who was unlucky enough to have summoned Caster, is found by Waver and Lancer in a half-dead state. Lancer notes that Caster vivisected him alive (because of Kariya's Crest worms), then healed him and left him, barely, but still conscious. A disgusted Lancer gives him a Mercy Kill.
- Armor-Piercing Question: Waver unintentionally asks one to Irisviel.Waver: The Einzberns helped to create this ritual in the first place, sure. But what kind of person are you, and what do you want out of it?
- Boom, Headshot!: Similarly to canon, Ryuunosuke, implied to have still been shot by Kiritsugu. He may have been getting off light, because Lancer had been about to do the job himself seconds beforehand.
- Bridal Carry: Apparently the most efficient way for Lancer and Waver to travel. Waver only really seems to mind the altitude.
- Cooldown Hug: Lancer gives one to Waver shortly after they found Caster's "workshop". It is described as rather awkward.
- Deceased Parents Are the Best: As in canon supplemental material, Waver's parents are both dead long before the story begins.
- Dramatic Irony: One master tells another to surrender the war or die. Except this time, it's Kayneth making the demands and Lancer who survives.
- Eldritch Abomination: Caster, obviously, but also his tentacle familiars implied to now be somehow fused with parts of Kariya's insects, possessing compound eyes and too many legs.
- Extreme Doormat: Waver is sure Lancer would apologize for hurting his hand if the youth tried to hit him. He finds it very frustrating.
- Foil: Kayneth, to Waver. Both of them entered the war for recognition, but one is a symbol of the current class divide chasing further prestige, and the other is a reformist looking to draw attention to his ideals.
- For Want of a Nail: The entire purpose of the fic - everyone gets a Servant another Master received in canon. Waver gets Lancer, Kayneth gets Berserker, Tokiomi gets Rider, Kariya gets Caster, Kiritsugu gets Archer, Kirei gets Saber and Ryuunosuke gets Assassin.
- Fighting Irish: Lancer, by definition.
- Go-Karting with Bowser: Not a strictly villainous example, but Waver and Lancer end up sharing a table at a cafe with Irisviel and Gilgamesh.
- Heroic Safe Mode: Waver shuts down after Caster's defeat, having had a front row seat to Enuma Elish and seeing a crystal clear example of how far out of his depth he is.
- Heroic Self-Deprecation: Lancer refuses to call himself a "hero" and generally has a pretty low opinion of himself on most things. Waver, being confused and frustrated about this, tries to snap him out of it.
- I Kiss Your Hand: Lancer kisses the back of Waver's hand after the latter uses the last of his command seals.
- Mercy Kill: Lancer gives one to the half-dead, but still conscious Kariya.
- Mundane Solution: When Lancer confesses his face is bound to make any woman fall in love with him, Waver asks him if he tried to cover the cursed birthmark. Lancer's expression afterwards plainly screams "I am such a dumbass". He feebly tries to convince Waver just as much as himself that surely a divine curse can't be so easily countered, much to his frustration when it turns out it works.
- Waver's entire approach to combat magic ends up being this, even briefly stalling Volumen Hydragyrum with a simple chemical reaction.
- My Master, Right or Wrong: Lancer. It annoys and freaks Waver out a little.
- Nightmare Fetishist: Ryuunosuke, as per canon. He's so entranced with Caster's work that he orders Assassin to monitor Caster's massive summon and kill anyone who tries to take it out.
- Nothing Is Scarier: What exactly happened between Caster and his Master is never outlined in detail or given narrative attention. Only the results are shown, and given what they are, do you really want to know?
- Pride: Gilgamesh, of course. Irisviel uses this to her advantage to talk him into avoiding a fight with Berserker and letting Kiritsugu and Maiya take care of him, by suggesting it would be "beneath him".
- "The Reason You Suck" Speech: Lancer gives a short, but effective, one to Kayneth.Lancer: It is remarkable, how this world has changed. Even shadows can speak and think themselves worth notice now. For surely none who calls themselves superior would hide within the dark like a coward, would they?
- Royals Who Actually Do Something: Archer. With the Masters in complete disarray during the Mion River battle and Saber instructed not to use her Noble Phantasm, Archer becomes the first Servant to reveal his identity in-universe...with Enuma Elish.
- They Call Him "Sword": A given considering the series, but to date even Waver doesn't know Lancer's real name. He finally puts it together after a Rousing Speech involving a tale from Lancer's childhood. It's the legend of Cu Chulainn.
- Too Dumb to Live: Kiritsugu ignores Gilgamesh and openly treats him like a tool. He would be dead already if Irisviel wasn't smart enough to know how to handle someone like the King of Heroes.
- Serial Killer:
- Ryuunosuke Uryuu is hinted at being even more effective than in canon. It's heavily implied that he uses Assassin for randomly killing people all over Fuyuki City.
- Caster remains one. As evidenced by his workshop where Lancer and Waver discover the remains of his handiwork along with his half-dead Master.
- Teeth-Clenched Teamwork: Servant-Master teams are even more mismatched than the original work. The only team which isn't endangered by infighting or incompatibility is Lancer and Waver.
- Tranquil Fury: Lancer, when he sees the nightmare that is Caster's workshop.
- Tsundere: Waver. Especially at the beginning, but he slowly warms up to his Servant.
- Would Hurt a Child: Caster and presumably Ryuunosuke, as in line with canon. Waver notes that, upon discovering Caster's workshop, that none of the bodies that he can identify look older than ten.