A completed LightNovel/TheFamiliarOfZero story which is not a crossover at all, it is primarily a romance fic which the author describes as his version of season 4. It examines Tristain's separation between nobles and commoners somewhat as well as a few societal differences. Mostly, though, the story just explores some CharacterDevelopment as everyone tries to get what they want without crossing the MoralEventHorizon. Then, when it looks like everything might just work out, [[spoiler:an assassination attempt sends Saito, Siesta, Henrietta, Tabitha, and Louise to Saito's world.]]

It is found [[https://www.fanfiction.net/s/7805384/1/Jus-Primae-Noctis here]].

!!Tropes present in this work include:

%%* BedmateReveal
* BelligerentSexualTension: Between Saito and all the girls.
* [[spoiler:BittersweetEnding: Everyone lived a long and happy life, and the countries were mostly prosperous as well as gaining parliaments, FridgeLogic tells us that Louise and Saito are both dead in the DistantFinale, as their grandchildren have inherited the void mage and Gandalfr mantels, the former of which is only passed on by death.]]
* ChivalrousPervert: Old Osmond. He single-handedly arrangs Longueville's HeelFaceTurn.
* CurbstompBattle: The first has Saito face down a bunch of magicless thugs who were threatening his girls. Later he cows a bunch of army generals by threatening to do this to them.
%%* CutenessProximity
* DeliberateValuesDissonance: Look up the meaning of the title. [[spoiler:It roughly means ''Right of the First Night'', and refers to a lord's right to claim the virginity of any peasant woman under his authority, as well as allow or forbid her marriage. This is a normal and acceptable thing in Halgenkia.]]
* DemotedToExtra: Kirche may show up once, and Tiffania barely appears except in the side-plot.
%%* DistantFinale
* DysfunctionalFamily: The Gallian Royals.
* EstablishingCharacterMoment: An interesting in-universe version. [[spoiler:When Saito's mother starts wailing on Saito for worrying her so much Louise is the only one to grab her arm and stop her, which is why Saito's mother takes Louise aside later and gives her support and advice.]]
* FromBadToWorse:
** First Henrietta needs to get married, then there're potential problems over her choice in groom, which culminates in [[spoiler:an assassination attempt that sends them to Saito's home world and leaves Tristain on the verge of civil war.]]
** Also, from Louise's point of view, [[spoiler:just after she, Siesta, and Saito manage to work out how they relate to one-another—Siesta is Saito's maid and Louise's subordinate, which is enough to satisfy Louise's status obsession—her closest and oldest friend who also outranks her feels the need to force her way in.]]
* GreenEyedMonster: Granted, take a look at how the other girls interact with Saito and you'll wonder if she's a little justified.
* HalfBreedDiscrimination: Against Tiffania, but downplayed.
* HappinessInSlavery: Siesta claims that she has this as long as it's Saito. Given that she made the choice to become his property it seems believable, but it squicks Saito at first.
* HeelFaceTurn: Longueville, with Osmand's help and oversight.
* HeroicBSOD: Tabitha breaks down wailing when she discovers [[spoiler:her branch of the Gallian family was responsible for trying to kill Saito's grandparents.]]
* HoYay: Invoked and subverted. Professor Colbert has Malicorn announce his love for Saito, who reacts badly, but it was all a plan to help Saito understand why Louise is so angry with him.
* IgnoreTheFanservice: Enforced. The story has Colbert tell Saito that his relationships would all improve a lot if he managed to do this.
* IWantMyBelovedToBeHappy: Louise has moments of this where she thinks Saito has definitely chosen someone other than her.
* KissingCousins: Henrietta and Wales were this in the past. [[spoiler:Saito and Tabitha turn out to be a distant version of this, with his grandmother a Gallian Void Mage and his grandfather her Gandalfr.]]
* LeaveTheTwoLovebirdsAlone: Inverted. Louise accidentally does this at the temple, and then realizes it, runs backs, and interrupts them.
* LetsWaitAWhile: Downplayed. Louise wants to wait [[spoiler:until she, Saito, and the others get back from Saito's home world]] before they have TheirFirstTime.
* LoveCannotOvercome: Louise is implied to worry about this. [[spoiler:Turns out love and honest communication can overcome, though.]]
* LoveEpiphany: [[spoiler:Saito has this about all the girls at the same time, though he still puts Louise first.]]
* LoveObstructingParents: Averted. It takes a while, but the parents that are seen eventually come to accept the situation.
* LoveRuinsTheRealm: This is brought up, but really it's ambitious traitors that ruin the realm. Love actually brings it peace and prosperity.
* MagicContractRomance: Saito, obviously. [[spoiler:Also his granparents, and it appears to run in the family.]]
* MamaBear: [[spoiler:We meet Saito's.]]
* MarryThemAll: Nope. [[spoiler:Not Kirche and Tiffania, at least, but he technically married Louise using the flower ritual before Saxe-Gotha, he marries Henrietta under Tristanian law, he marries Tabitha in a small ceremony conducted by his grandfather in his home world, and while it's debatable if he really marries Siesta, that doesn't stop them from being together.]]
* MassOhCrap: An entire country does one when their monarch goes missing.
* MemeticBadass: In keeping with canon, Saito is this in-universe. He brings up the battle against 70,000 when [[spoiler:telling the would-be rebels to sit down and shut up,]] and even though he really would be killed by the overwhelming odds this time he cows the other guys into surrendering.
* MoodWhiplash: An in-universe example. [[spoiler:Louise goes from metaphorically bearing her fangs at Siesta around Saito to bringing up Jus Primae Noctis once Siesta officially acknowledges Louise as her superior.]]
* NotSoStoic: Tabitha when she discovers [[spoiler:her relatives were responsible for trying to kill Saito's grandparents.]]
* OfficialCoupleOrdealSyndrome: Downplayed, but present until the end.
* OOCIsSeriousBusiness:
** Louise several times: [[spoiler:When she believes Saito has chosen Siesta over her she becomes very meek. Then when Henrietta expresses her desire to wed Saito Louise shows she is willing to throw away her name and title to stay with Saito as his maid, like Siesta.]]
** Henrietta [[spoiler:first when she expresses her desire to wed Saito in spite of Louise threatening to end their friendship, and then again when she confesses to Saito that she isn't a virgin.]]
** Tabitha utterly breaks down when she discovers [[spoiler:her relatives were responsible for trying to kill Saito's grandparents.]]
* PoorCommunicationKills: Technically one of the first things Louise canonically did was bring up how her being naked around a servant/human familiar of the opposite gender was no big deal, but it was left at that. If Saito had found out the ramifications and implications, it might have saved some grief these past few years. Beyond that the author mostly averts this.
* RelatedInTheAdaptation: [[spoiler:Tabitha and Saito are related in this fic, which becomes a major plot point after the reveal that Tabitha's relatives, especially Joseph, were behind the deaths of Saito's grandparents. This also makes Saito related to the Gallian Royalty as he is Tabitha's cousin.]]
%%* ShipperOnDeck
%%* SleepCute
%%* SuccessionCrisis
* TrappedInAnotherWorld:
** Saito was, though [[spoiler:he technically knew a way back. Then the assassination attempt switches this, and now Saito's home but Tabitha, Seista, Louise, and Henrietta are trapped in his world.]]
** We later find out that this happened to [[spoiler:Saito's grandparents: his grandfather summoned to Halkeginia by his grandmother, a void mage. They both fled back to Saito's world, where she peacefully lived out the rest of her days.]]
* [[spoiler:TogetherInDeath: Fridge Logic implies that Louise and Saito are this during the DistantFinale.]]
* TheirFirstTime:
** [[spoiler:Who gets Saito's is a point of contention among the girls, but he and Louise both vote for her to get it, though the others make half-hearted attempts at claiming it for themselves. At the end Saito and Louise disappear off to her room to share theirs.]]
** [[spoiler:Also, Henrietta tearfully reveals to Saito that she had hers out of wedlock with Wales. Contrary to her expectations, Saito accepts this and is glad she shared that with the man she loved.]]
* UnresolvedSexualTension: Once the circumstances are cleared up, Louise states that she's fine with Saito having this with other girls provided she gets to resolve hers first.
* TheWarRoom: Downplayed, but several people have councils of war about the growing crisis after [[spoiler:Henrietta and the rest are sent to Saito's world.]]
* WhamLine: "I see, well, I wouldn't think that you would [know how to get home]. [[spoiler:That's not a Gandalfr's job after all]]."
* WouldntHitAGirl: Saito won't do it verbally. At least, he wouldn't. The story starts with Louise angry at him never telling off any of the other girls despite professing to love her, so he finally gets people together and sorts everything out, laying (still somewhat murky) boundaries.
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