Xendra

A Buffy the Vampire Slayer/Xena: Warrior Princess crossover fanfic by Diane Castle, author of The Secret Return of Alex Mack, Hermione Granger and the Boy Who Lived and numerous other well-regarded fanfics.

After losing a bet with the Sunnydale High football players, Xander and several other guys have to dress as female characters on a certain fateful Halloween. Xander chooses to go as Xena: Warrior Princess, and finds a chakram prop in Ethan Rayne's costume shop. While Xander's transformation ends when Ethan's spell is broken, it is not permanently gone; Xena's memories (but not physical abilities) stay with him. Not only do they generally affect his academic performance for the better, he finds himself able to teach Buffy Xena's swordsmanship even if he can't quite master it himself, and he becomes focused on trying to reproduce her skill with a chakram without breaking (or worse, severing) his fingers. Meanwhile, Xena's lingering presence in the back of his head affects his friendship with Willow for both better and worse, but it finally settles down into a very positive and intimate romantic relationship between the two.

However, Xander's night as Xena ultimately causes him more problems. Daniel Osbourne has grown obsessed with finding the tall brunette he saw dressed as Xena on that Halloween night, and when he blackmails Amy Madison into casting a spell to find her, Xander finds himself forced back into a female body, only this time without Xena along for the ride. He's eventually returned to his birth gender, but to his dismay and mortification, the transformation is re-invoked several times -- including when Xander's true form is so grievously injured that changing him back would lead to his very quick death. Xander must then masquerade as Giles' very real niece, The Honorable Xendra Helaine Devaney Giles, while working with the other Scoobies to protect Sunnydale when Buffy runs away after dealing with the demon Acathla.

And that's just the beginning -- Xendra is a massive and engaging exploration of For Want of a Nail against the background of BTVS, with changes at first small but then snowballing until about the only things familiar about the story's version of the series' later seasons are the Big Bads. Different circumstances lead to different developments and different approaches to the Big Bads -- and different consequences for nearly everyone involved. And some familiar faces never appear at all.

It can be found here.

"How am I gonna tell 'em that I'm a magic-wielding lesbian sex-having witch who believes in the supernatural and turned her boyfriend into a girl? And I've eaten bacon!"
 * Abandoned Warehouse: The frequency with which they turn out to be vampire lairs is lampshaded and mocked by the Scoobies.
 * "Lestat" uses such a warehouse for the lair of his band of vampires, but approaches it with dangerous genre-savviness.
 * Abnormal Ammo/Depleted Phlebotinum Shells: After seeing "Dragon's Breath" shotgun shells in use, Willow and Xander create "Slayer Shells":  a standard-sized shotgun shell that contains not only lead shot but Cold Iron and silver pellets, cubes of Quebracho (the hardest wood in the world), tiny steel crosses, and magnesium shards.  There are few demons and no vampires who can survive being on the business end of one of these.
 * Acquired Poison Immunity: What it turns out that the Cruciamentium is really about -- building up the Slayer's immunity to a number of otherwise deadly toxins of demonic origin.  The immunity is carried by the Slayer Spirit, so even if a particular Slayer dies from the Cruciamentium, the next will have improved resistance to the poison(s).
 * Anachronism Stew: At least in regards to pop-culture references.  While the story ostensibly starts during the series' canonical time period (1996-2002), the characters routinely invoke, quote or cite works that wouldn't come out until well afterward.
 * Xena's memories, at least to Xander. He notes that she has recollections of events that most definitely did not all take place in a single human lifespan.
 * And I Must Scream: Faith while working for the Mayor, after she discovers that she cannot refuse to kill someone she doesn't want to, no matter how hard she tries.
 * Anything That Moves: Andrea at least gives this impression to the Scoobies for a while after her transformation, but she quickly settles down with a boyfriend.
 * Arson, Murder, and Jaywalking: Willow's panicked babble from the end of chapter 102, at the prospect of her parents both coming home at an inopportune time:

"Andrew handed a small camera system to the biggest monkey demon and sent them on their way. He cackled, "Fly! Fly! FLY!" Lance was looking into a battery-powered monitor hooked up to a receiver. "Isn't it 'fly my pretties, fly'?" "No!" Andrew complained. "That's not what she says! Go watch the damn movie!""
 * Asskicking Equals Authority: Because the Scoobies rescued the DRI base and killed Adam, they ultimately get a lucrative government contract as consultants to the reconstituted Initiative.
 * The Atoner: Faith, after she's freed from mind control.
 * Attractive Bent Gender: Definitely in play for everyone subject to a gender transformation in this story.
 * Back from the Dead:
 * Faith flatlines twice on the operating table after Buffy nearly kills her, but is revived and eventually makes a full recovery after an extended coma.
 * After a failed attack on Glory, Kennedy is smashed into a pond, where she drowns and technically dies -- until she is rescued, receives CPR and is revived.
 * The Baroness: Invoked (through G.I. Joe) as a model for Xander/Xendra's early "Goddess Messalina" act.
 * Bavarian Fire Drill: Xander (as "Xendra Giles") when the Council team visits Sunnydale.
 * Also the repeated visits to the morgue to pre-stake vampires during the reign of "Lestat".
 * Beam Me Up, Scotty: Invoked in-universe in part 18:

""Both!" Willow grinned. "Some from Column A and some from Column B.""
 * Becoming the Mask: Forced to play the role of Giles' elegant, well-educated niece, Xander finds himself starting to think with her vocabulary and picking up behaviors and tastes alien to his earlier self, and worries that this might be the case.
 * Blackmail Is Such an Ugly Word: Oz quotes the trope name word-for-word as his way of informing Amy that she's going to be casting a spell for him -- or else.
 * Blood Magic: Required for Andrew's summons of the flying monkey demons.
 * The discovery of the uses for virgin's blood leads Willow and Xander to warn their non-Scooby friends and help them hook up with like-minded persons of the appropriate sex.
 * Bow Chicka Wow Wow: Invoked by Willow when speculating on playing "pizza delivery girl" sex games with Xander.
 * Brainwashed and Crazy: Faith, after evil!Amy tricks her into accepting a "clarity of thought" spell which actually turned up all her bad traits and turned down her good ones.
 * Bratty Half-Pint: How the Scoobies (including Faith) initially see 14-year-old Slayer Kennedy DaSilva.  They call her "Veruca Salt", "Princess Whinypants" and other less-than-flattering names -- at least at first.
 * The Caper: A lot of Scooby plans work out like classic capers, especially the plan to tap into the Sunnydale Army base's comm system so Willow can untraceably crack high-security government computer systems.
 * Chekhov's Gun: There is no dearth of them:  just about anything that initially seems to be a "one-off" event or item eventually returns.
 * There are also Guns presaging certain reveals later in the story -- such as comments how some things Quentin Travers has done as head of the Council seem out of character compared to his general dickishness.
 * Comic Book Time: Invoked at one remove when Xander delves into Xena's memories -- he notes that she seemed to have witnessed or participated in historical events that were centuries (sometimes many centuries) apart.
 * Continuity Cameo: The arrival of a tween-aged Vi (complete with knit hat) on the Summers doorstep as the fourth Slayer at the very end of the story.
 * Conversational Troping: Despite the anachronism, the Scoobies appear familiar with troping jargon and use it a few times, such as describing Cordelia as an Alpha Bitch to Faith.
 * Cool Big Sis: After the revelation of the all-but-literal sisterhood of all Slayers, Buffy and Faith take this role for Kennedy -- and when a thirteen-year-old Vi shows up in the final paragraphs of the story, Kennedy is delighted to get her turn at it.
 * CPR: Clean, Pretty, Reliable: Averted with Kennedy's resucitation at the renaissance fair; it works, but it's neither clean nor pretty, not with all that lake water involved.
 * The Cracker; Willow, in a rare non-malevolent (though admittedly still criminal) example.
 * Crossover: Very loosely.  Xander gains Xena's body, skills, and memories, but after Halloween ends is not her.  And he quickly discovers that while he knows all the ancient languages she knew, not all her memories of the ancient world are accurate either because of different timelines, because modern history is missing information, or both.
 * Frank Gannon came out of retirement to take a job on the Sunnydale police force. (Turns out he's part Brachen demon, and terrified of Buffy.)
 * Dame Not-Appearing-In-This-Fanfic: Dawn, whose creation is one of the things disrupted by Xendra's existence.
 * Dangerously Genre Savvy: "Lestat", which makes him and his followers particularly hard to handle for the Buffy-less Scoobies.
 * Demonic Possession: Played with when a grief-stricken and enraged Tara uses a black magic ritual to give her body to a dangerous demon in order to get revenge on Glory -- but it's clear she's possessing the demon more than it's possessing her.
 * Doorstopper: 281 chapters and 960,111 words written over seven years.
 * Double Standard Rape (Female on Male): Averted in the aftermath of.
 * Emergency Transformation: One is effectively performed when Drusilla triggers Xander's third change to make him an ersatz Jenny Calendar with which to torment and torture Giles.  Xander at that point is paralyzed by a spinal injury and not far from death from other wounds; when he is forced back into teen!Xena form all his injuries vanish (but remain, in abeyance, in his male form, complicating plans to change him back).  A couple years later Xander suffers another serious injury and remains female until the necessary ritual can (again) be performed.
 * Late in the story, Willow deliberately includes a dying Riley Finn in Xander's transformation to Xendra to save both their lives.
 * The End - or Is It?: The story ends with the defeat of Glory, expanding numbers of Slayers, the dawn of a new era of Council support for them... and a conclave of villains planning how to take advantage of the vacuum created by the destruction of the Circle of the Black Thorn, the Senior Partners, Wolfram and Hart, and Glory.
 * Epiphany: As a result of a Vision Quest all three Slayers -- and Xendra -- undergo, they experience personal and group epiphanies which lead to, among other things, the acknowledgement that the Slayers are more than metaphorical sisters, and Faith finally accepting Xander and Willow's affection for her -- and hers for them.
 * Even Chaos Has Standards: Ethan Rayne's patrons -- a variety of gods and goddesses of Chaos -- force him to cooperate with the Scoobies and the DRI to find a way to reverse the effects of his Halloween spell on the children of Sunnydale, because it made it possible for them to become Glory's demonic minions.
 * Evil Laugh: Corrupted!Amy gets a few in the privacy of the Madison home.
 * Fandom-Specific Plot: Starts off as a bog-standard YAHF (Yet Another Halloween Fic).  Arguably it's one throughout, but it's an epic exploration of the idea with some dramatic changes that upset the status quo.
 * Fantasy Gun Control: The Council does not equip Slayers with guns and other modern weapons because of a compact made with the demonic forces in the fifth century which keeps the Earth from being overrun outright, and which limits what they may train the Slayer to use against them.  It comes up for renegotiation every thousand years, and the Council only barely got crossbows approved at the last one, in 1451.
 * First Law of Gender Bending: Hits Xander with a vengeance.  First he's transformed into Xena on That Halloween.  Then a spell performed to find the Halloween Xena lookalike briefly turns him into a teenaged Xena.  Then Drusilla uses a stored spell to turn him into teen!Xena again.  While that's undone a few months later, Amy and Willow -- trying to learn how to store a spell in a crystal as Drusilla had used -- find their only success is with yet another instance of the spell to turn him into Xena, which leads to multiple transformations (which Willow or Amy can undo afterward).  It eventually reaches a point where any time the Scoobies need an untraceable female or an extra near-slayer-level fighter, Xander's gender gets toggled.  And after  twice a week.  Eventually the magical principle called the Law of Precedent (the more a particular magic has been performed, the easier it becomes to perform) takes over, and it seems that any sufficiently strong magic in Xander's vicinity will turn him into Xendra.
 * Initially averted with Andrew, who was turned into a teenaged Princess Leia, and wanted desperately to be turned back into a girl because the experience led him to acknowledge that he's transgender. However, he gets permanently transformed as part of undoing Xander's initial stint as Xendra.
 * After getting caught in one of Xander's transformations, Wesley Windham-Price finds that he too is affected by the Law of Precedent and is prone to turning into "Leslie Linda Price". And when he gets involved with Tara Maclay -- a lesbian who is frightened by his male aspect -- he chooses to spend all his time with her as a woman.  At the end of the story he chooses to be a woman full time, and lets his male identity "die".
 * For Want of a Nail: Xander's different costume and Halloween transformation cause changes that quickly snowball, including Jenny Calendar's survival and Oz's death -- and that's just to start with.
 * Foreshadowing: Early concerns about the long-term effects of their Halloween transformation on the children of Sunnydale turn out to be very valid.
 * Fun with Acronyms: The term the Scoobies come up with for the DRI forces before they find out its real name:   Military Operation Futuristic Outsiders, or "MOFOs", for short.  They keep using it for giggle value even after they find out the organization's real name.
 * When the commander of the re-organized DRI is uncomfortable using "magic" in his official communications with his superiors, Willow offers a euphemistic acronym he can use: SHADETREE, for "Symbology- and Heuristics-Affected Directed Energies Through Recondite Esoteric Egresses".
 * Gadgeteer Genius: Willow is a realistic version of this trope, creating all manner of gadgetry ranging from ammunition to electronics, and at times coming close to Magitek.
 * Gender Bender: Xander/Xendra, Andrew/Andrea, Wesley/"Linda"...
 * God Guise: Faith (equipped with "Mister Clubby" and backed up by a DRI team), convinces a military Search-and-Rescue team that beat them to a downed DRI helicopter that she is a Norse goddess in order to acquire their cooperation.  It helped that they had already their own Agent Mulder and a few experiences with the supernatural.
 * Good Cop, Bad Cop: Used by Xander and Andrew to get Tucker to reveal who makes spell crystals; lampshaded during the planning beforehand.
 * Willow's parents do this when interrogating Willow and Xander.
 * A Good Name for a Rock Band: Invoked by name several times, such as with "Gunn and the Broodmeister".
 * Good People Have Good Sex: Willow and Xander (regardless of the gender he's in at the time)... and Faith (eventually, with Xander and Willow's encouragement -- and participation).
 * Hero of Another Story: In the early part of the story there is an extended sequence where we see the Scoobies working to keep Sunnydale safe while Buffy has run away as in canon, something that was glossed over in the series.
 * Heroic Sacrifice: How Ethan Rayne ultimately breaks the spell that turned children into Glory's minions.
 * Hidden Depths: Faith, who in unguarded moments with Wesley discusses (and quotes) Sherlock Holmes stories, turns out to be a Master of Disguise and is far more complex than she usually lets anyone see.
 * Hollywood Hacking: Averted with Willow in general, and specifically with the effort needed to plant a circuit board permitting the Scoobies to intercept calls to and from the Sunnydale morgue in its PBX cabinet.
 * Impossible Task: What the Scoobies and the Watcher's Council ensure that reassembling the Judge will be in the future.  The Council arranges for some pieces to be dropped in deep ocean trenches, others to be buried in Antarctica, and one to even be shot into space.  Willow keeps a piece and after determining that she can't find a way to kill it, freezes it with liquid nitrogen, shatters it into innumerable tiny shards, and then has those shards mixed into fresh concrete being poured as the foundation of a building.
 * Improbable Weapon User:  Xander keeps up the use of chakrams in combat.  Even though he never gets as good as Xena with them in either form, he does become quite skilled.  They're also advantageous in that most vampires and demons don't know how to handle them, frequently ending up missing fingers when they try to catch the weapons -- and Xander makes his chakrams engraved with tiny crosses for that extra special something on top of their razor-sharp edges.
 * In Spite of a Nail: Some events in the months immediately after That Halloween run essentially the same despite the absence of Xander's "soldier boy" memories to help them along as they did in canon.  For instance, Willow and Xander essentially build their own rocket-propelled grenade from scratch to deal with the Judge.  But the further along events get, the larger the divergences get, until things are so different the absence of Xander's soldier memories doesn't matter at all.
 * Invisible to Normals/Sunnydale Syndrome: Starts breaking down, at least slightly, in the wake of the Mayor's explosive death in the middle of a park, and the subsequent distribution of tons of snake meat across the landscape.
 * Let's You and Him Fight: The Scoobies use this on the demonic targets that are too big for them to deal with directly, first by manipulating the Circle of the Black Thorn into killing each other out of paranoia, and later by exploiting a magical loophole to drop Glory into the home dimensions of the Wolf, Ram and Hart (the first two of which she kills).
 * Loophole Abuse: A few examples:
 * Willow figures out that the Council's seeming "evil" and dickishness is actually a cover for protecting the Slayer the only ways they can given the demonic compact they are party to but cannot reveal due to its terms, at risk of breaking it. However, the compact had no provisions for third parties deducing and revealing its existence, and when Willow does so... nothing bad happens.
 * Similarly, while the Council is banned by the current version of that compact from equipping the Slayer with modern weapons, it says nothing at all about third parties doing so on their own initiative.
 * The Scoobies figure out that an unanticipated side effect of destroying the L.A. headquarters of Wolfram and Hart could drop Glory into the laps of the Senior Partners -- and so they lure her there and use her to effect the very destruction that then ejects her into the demonic realms.
 * Magitek: By midway through the story, Willow is freely mixing magic and technology to do some of the things the Scoobies need.
 * Making Use of the Twin: In-Universe example -- Wesley's female form is apparently close enough in appearance to Faith that with the right make-up they can pass as twins, and in the aftermath of Wesley's second transformation (and the destruction of all his IDs and papers in the process) they exploit this to get back to the United States together.
 * Metronomic Mook Massacre: Buffy does this to "Skip", a metal-skinned demon much larger than her, during the attack on the Hyperion.
 * The Mind Is a Plaything of the Body: Xander worries constantly about this even after he's no longer stuck as "Xendra", although after a year or so it finally damps down.
 * Mistress of Disguise: When sharing her identity with female!Wesley to get them both back to the United States, Faith turns out to be very adept at disguising both herself and "Linda", with multiple guises for both.
 * Nail'Em: Xendra uses a high-powered nailgun to slow down and eventually incapacitate Adam long enough for Buffy to deactivate him during the raid on the DRI base.
 * Named After Somebody Famous: Kennedy DaSilva and her mother McKinley Williams; apparently her mother's family has a tradition of Presidential names.
 * Named Weapons: The Hammer of the Troll Gods allows its "approved" users to rename it.  Buffy calls it "Mister Clubby", and as far as Willow can tell with her magic, it likes the name.
 * No Celebrities Were Harmed: "Linda Loshayn", a transparently-obvious Expy of Lindsay Lohan with whom Kennedy becomes involved. (Interestingly, Lohan herself is referenced a couple times and seems to be a different person entirely.)
 * No Endor Holocaust: Averted, at least theoretically, in that based on Xander, Andrew/Andrea and several other people with permanent fallout from That Halloween, the Scoobies are concerned about the possible long-term aftereffects on the children that were also transformed.
 * No Ontological Inertia: Most if not all of the spells cast by the Mayor gradually (or suddenly) collapse on his death.
 * Oh My Gods: Xander, thanks to a bit of personality overlap from Xena, is given to occasionally saying things like "the wrath of Zeus".
 * Omnidisciplinary Scientist: Willow.  By the time she's college-aged, she's already got Bachelor's degrees in multiple fields, and is working on several Master's and at least one Ph.D.
 * One from Column A and Two from Column B: Willow mentions that she cloned a computer from Wolfram & Hart to use as a cover for some hacking and is asked if she used magic or technology.

"Even Cordelia was eating a human-sized lunch, when normally she was on the salad-and-a-toothpick diet. That was definitely a sign of the apocalypse. Okay, he should stop making jokes that included the words ‘sign of the apocalypse’ because, well, real apocalypses that were happening all over the place. Who the hell decided there should be an apocalypse twice a year? Okay, the word ‘hell’ there was probably totally relevant, because things from hell dimensions were probably a part of the whole mess anyway. And hadn’t Giles told him that the things that created vampires were maybe still around in their own hell dimensions? Jerks. Nah, he should keep making jokes about the signs of the apocalypse. Because if you couldn’t make ‘signs of the apocalypse’ jokes anymore, then the apocalypsers have already won. Or something like that."
 * One of the Seven Signs of the Apocalypse:  In chapter 17, Xander briefly ponders the wisdom of joking about the trope on the Hellmouth:


 * One Steve Limit: Averted with "Linda Leslie Price", Wesley's female alter ego, and "Linda Loshayn", Kennedy's celebrity girlfriend.
 * Operation: Blank: When making plans to expand their intelligence on the DRI, the Scoobies spend some time discussing what to call their plans, at one point invoking this trope.  But ultimately this is averted, as they can't agree on any of the words to fill in the "Blank", and simply end up calling whatever they do "The Op", "The Other Op", and "The Other Other Op", as needed.
 * Possession:
 * Post-Modern Magik: Willow becomes a master of this, reaching a point where she can deconstruct ancient, complex and time-intensive spells or formulae, determine their "active ingredients", and reconstruct them into simpler and often more-effective forms using off-the-shelf components.  She eventualy extends this into true Magitek.
 * Put on a Bus: Darla, and then Angel, are shipped off to the Vatican to protect them from Wolfram and Hart.  They never return during the course of the story.
 * Reality Ensues: One of Castle's trademarks, nowhere better seen than with the Hammer of the Troll Gods.  While to its "authorized users" it is heavy but easily wieldable, to everyone and everything else -- including vehicle suspensions, elevators, furniture, and concrete slabs -- it's several tons of dead weight.  With all the unwanted effects that brings. Xander eventually builds a "baby bed" out of heavy truck parts just to give Buffy a safe place to put it down.
 * Reasonable Authority Figure: In addition to Joyce's canon status as this after she learns about the supernatural, Willow's parents also get on board with the team after the truth is revealed to them.
 * Redemption Equals Death: After Ethan Rayne's Heroic Sacrifice is discovered, the Scoobies discuss whether this might be the case -- insofar as what his patrons would consider a redemption, at least.
 * The Reveal: Initially the Council looks just like the Jerkasses and near-villains they are in canon.  But... early on it's unexpectedly shown that many of the "evil" or just plain dickish things they (particularly Quentin Travers) do -- including things like the Cruciamentium -- are forced upon them by or are ways to get around a compact with demonic forces that prevents the Earth from being overrun outright.  The terms of the agreement go so far as to outright forbid telling anyone other than the highest echelons of the Council what's really going on, at risk of breaking the compact and opening Earth up to outright invasion.  For much of the rest of the story the contrast between the Council's real motives and purposes and what the Scoobies think they are makes for an interesting undercurrent to the plot.
 * Rings of Death: "Xena"'s chakram, and Xander's adoption of the weapon himself after that Halloween.
 * Running Gag: The early disagreement over the proper collective noun for a group of vampires:  "sparkle", "kiss", or "clot"/"coagulation".
 * Between Willow, Xander and Faith, marshmallow cream.
 * People making the "Home Alone face". Even Joyce gets in on it!
 * Second Law of Gender Bending: Andrew/Andrea, very much so.
 * Xander/Xendra initially worries about it constantly, but eventually comes to a kind of equilibrium state where he's equally comfortable as either. Of course, Willow being intensely into both of his forms helps a lot.
 * Wesley/Linda is an odd case. Wesley does not come to particularly prefer his female form, but because it makes it possible to be with the woman he loves, he chooses to become "Linda" permanently.
 * Self-Deprecation: Xander's sincere conviction that he is stupid -- despite being able to not only convincingly masquerade as "Xendra Giles" in the presence of Watchers Council members but to impress them with "her" intelligence, not to mention his frequent contributions to complex and sophisticated discussions and plans with Giles and the Scoobies.
 * Faith has some manner of inferiority complex when it comes to people with a better education than she has; under the effect of a spell that essentially intoxicates her, she breaks down and cries about how intimidated they make her feel.
 * Significant Anagram: "Linda Loshayn", the name of Kennedy's Hollywood starlet girlfriend late in the story, is an anagram of "Lindsay Lohan".
 * Sitting on the Roof: Xander takes to doing this for a few weeks when he's feeling estranged from the Scoobies after Angel returns from Hell.
 * Society for Creative Anachronism: The Scoobies start carrying their weapons around in dufflebags with prominent SCA labels and logos.
 * Spit-Take: Several instances and near-instances, usually set up and triggered as a prank.
 * Spoiled Brat: Kennedy DaSilva, the third slayer.  The Scoobies refer to her as "Veruca Salt" and other less-flattering names after they first meet her.  However, Giles and Wesley note that she can turn it on and off at will, and suspect that it may be as much a deceptive act as Buffy's "airhead" and Faith's "sexbomb" personae.
 * To the Pain: "Messalina"'s "torture" of Kevin to get information on "Lestat"'s little band of vampires and followers is almost entirely stagecraft and suggestion.  The only real pain inflicted on him are a couple slaps with a riding crop; he breaks when what he thinks is a dentist's drill is simply brought close to his face.
 * Transformation Trinket: The one-use crystals holding the spell that turns Xander into Xendra.  After a few changes he acknowledges that it's occasionally a necessary and good thing to be able to change if needed, so Xander tends to carry one with him at all times.
 * Transgender: Andrew, who was transformed into Princess Leia on Halloween, very much wants to be back in a girl's body.
 * After a year or two, Xander becomes surprisingly comfortable switching genders as needed for both Scooby business and private fun with Willow.
 * Ultimately, Wesley chooses to become a woman full-time because it's the only way he can be with Tara.
 * Triang Relations: Xander and Willow are open to a Type 8 relationship with Faith, but because of her self-esteem issues and guilt over having raped Xander years earlier they have trouble convincing her of their sincerity.  However, by the end of the story she has come around.
 * Undead Tax Exemption: Willow eventually acquires the means to create fully-realized histories and identities for "Xendra Giles"/"Xendra Harris" and "Leslie Linda Price", with genuine records in the appropriate government and private databases and all the attendant paperwork, including passports.  Reality Ensues, however, when she realizes she has to falsify years' worth of tax histories and returns for them.
 * Later, she uses the expertise gained then to create a fully-fleshed out legal identity for Angel to help protect him from some of Wolfram and Hart's schemes, and to protect the hotel as well.
 * Unspoken Plan Guarantee: Actively averted with the caper to tap into the Army base satellite dish.  We get all the planning and debugging of the plan, the practice of the physical aspects, and then its execution -- and nothing goes wrong.
 * Vision Quest: The Slayers and Xendra participate in one that leads to a set of individual and group epiphanies.
 * What Might Have Been: An In-Universe example occurs when Xander is told, in broad, vague terms, what would have happened if the Monks of Dagon had not turned Xendra into the Key; the reader will easily recognize the canonical fifth season of Buffy in the description.
 * Why Don't You Just Shoot Him?: Xander's suggestions (in the guise of Xendra Giles) to the Council members about what to do with Acathla are basically a "good guy" version of this trope.
 * Later, Xander literally asks this question about the Mayor shortly after they discover his nature; Giles offers a "hypothetical" answer that makes it clear it's already been tried, and has proven useless.
 * Xenafication: Happens literally to Xander.  Even after he's back to "himself", his female form tends to be stronger, better coordinated, and an all around better fighter -- although nowhere near Xena's level.
 * Yiddish as a Second Language: Willow uses far more Yiddish in this fic than she ever did on the show. Which is not surprising considering how much her parents use.  Amusingly, they tease her about her use of Yiddish.
 * Xander has picked up no small amount himself.