''[[http://www.fanfiction.net/s/2510565/1/Birds_of_a_Feather Birds of a Feather]]'' by [[http://www.fanfiction.net/u/380886/Solid_Shark Solid Shark]] is a ''[[Anime/MobileSuitGundamSEED Gundam SEED]]'' fanfic that takes place in an AlternateUniverse where there was a sixth SuperPrototype under construction at Heliopolis, and where former ZAFT AcePilot and Strategist Kenneth "Falcon" [=DiFalco=] joins the Archangel's crew as part of a wider plan he's running... one that will end the stalemated war...

One of the recommended fanfics for tropers, and possibly one of the most popular Gundam SEED fanfics around, ''Birds of a Feather'' takes the existing SEED setup and looks at it in a different light, while suceeding in telling an entertaining story that rivals canon. The author has described it as [[XMeetsY Ace Combat meets SEED]], with a dash of Franchise/MetalGear and [[Literature/HonorHarrington Honorverse]] levels of scheming.

Is followed by a sequel, ''[[http://www.fanfiction.net/s/3299267/1/Cry_of_the_Falcon Cry of the Falcon]]'', an AU of Destiny, and a prequel, ''[[http://www.fanfiction.net/s/3636180/1/Soldier_of_ZAFT Soldier of ZAFT]]'', covering Ken's ZAFT career before ''Birds of a Feather'' began.
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'''This fic contains examples of the following tropes, in addition to those already present in the source material:'''

* AbsurdlySharpBlade: Crossing with KatanasAreJustBetter, Kenneth [=DiFalco=] and the Gray Demons use blades forged from ''beam-deflecting armor'' - the same material as [[MobileSuitGundamSEEDAstray Astray Red Frame's]] [[{{BFS}} Gerbera Straight katana]].
* AcePilot: Canon aces, OC aces (the Gray Demons), MSV aces... the author was clearly demonstrating his love of ''VideoGame/AceCombat''.
* AnimalMotifs: Several, most notably Ken's own [[RedBaron alias]]. Not touched upon much, though fics inspired by it frequently take the motifs UpToEleven.
* AscendedExtra: A few, most notably Shiho Hahnenfuss. Outside of a couple of obscure manga appearances, she has two or three non-speaking background appearances in canon. Here she plays a sizable role, culminating in [[spoiler: killing Shani Andras.]]
* AscendedFanboy: In-universe example with Shinn in ''Cry of the Falcon''; here he's an admirer of the Grimaldi Falcon, and when he finds out that he gets to fly with Ken in combat... he doesn't quite squee, but the hero worship is obvious.
* TheAtoner: [[spoiler: Rau Le Creuset,]] in ''Cry of the Falcon''.
* BackFromTheDead: Also [[spoiler: Rau Le Creuset.]] Much to the displeasure of most of the world, including most allies of the man who gave the order.
* BadassCrew: The Gray Demons are mentioned to have been this before most of them were killed at Endymion. The Le Creuset Team are also this, which is why Ken makes a point of recruiting them into True ZAFT. On the Earth Alliance side, we have the Frighteners, an all elite unit based off of the British SAS.
* BadassLongcoat: Really applies to just about any ZAFT redcoat; more traditionally, Ken and Waltfeld both usually wear trench coats over their uniforms.
* BadassNormal: [[spoiler: Sophia [=DiFalco=], Ken's Natural sister, who manages to hold her own despite being outgunned for most of ''[=BoaF=]'']].
** [[spoiler: Major -later Colonel- [[ColonelBadAss Karen Willet]] is another. She's trained her body to Coordinator levels, sort of like Rock Lee from Naruto. She's actually able to use a Coordinator-type OS.]]
* BigDamnHeroes: When a battle goes badly awry for the Archangel's group late in the story, [[spoiler: none other than Lewis Halberton arrives with another rogue Earth Alliance ship, the ''Odin'', and, possessing the means to ignore the jamming hampering the ''Archangel'''s fighting ability, blasts the ambushers to dust bunnies, taking the time to deliver a PreMortemOneLiner to the EAF commander along the way.]]
* BiggerStick: Ken seeks for, and attains, the biggest stick in mecha technology... [[spoiler: and then gets it blown halfway to scrap metal in its first major engagement.]] The Earth Forces and ZAFT learn from his example in ''Cry of the Falcon'', constantly attempting to one-up each other.
** In ''Cry of the Falcon'', ZAFT's latest toy is the TRVF-51 Fianna, a variable fighter. Section Nine goes for the TRVF-51A model with nuclear reactors, N-Jammer cancelers and VPS to have a bigger stick... and because the full-spec Fianna is more complex than the basic Fianna & thus has a longer assembly time, they can only deploy four units in the time it takes for ZAFT to deploy two ''squadrons''.
* BreakTheHaughty: Falcon begins the series in full confidence in himself and his abilities. Subsequent events do much to strip him of this, leaving Ken a wiser person at the end of ''[=BoaF=]''. (Refer to WhatTheHellHero, OmniscientMoralityLicense and NiceJobBreakingItHero).
* [[ChekhovsBoomerang Chekhov's Boomerang]]: [[spoiler: Ever wonder what happened to Mu's [[AttackDrone Mobius Zero]] after they reached Earth? Ask Heine Westenfluss.]]
* TheChessmaster: Ken, fullstop. The man is always running one plan, and has at least two backups. [[spoiler: He's only caught off-guard three times in the fic.]]
** Doesn't quite qualify for MagnificentBastard status, though, if only because when his plans ''do'' fall apart, so does he.
* CloningBlues: [[spoiler: Ken is speculated in-story to be a clone of Al Da Flaga, but is stated to actually be the result of a form of postmortem artificial insemination, making him and Mu brothers. His usual [[TheRival rival]] and former protege [[TragicMonster Victor Tempest]], on the other hand...]]
* TheCameo: [[Anime/MobileSuitGundamSEEDDestiny Destiny's]] Heine Westenfluss appears in the final battle, playing a small but notable role, [[spoiler: almost killing [[GundamSEEDAstray Morgan Chevalier]]]].
* ColdSniper: [[GhostInTheShell Saito]] fills this role in his appearances. Also, [[spoiler: Ken himself,]] when he's operating in that capacity.
* ColonelBadAss: Technically a Commander, but arguably Rau Le Creuset. In addition to his canon [[MagnificentBastard Magnificent Bastardry]], during the GrandFinale [[spoiler: he fights off almost every ace True ZAFT has in succession, several of them simultaneously, before finally being caught in the blast from a WaveMotionGun.]]
* CommonKnowledge: Thanks to the author naming the Neutron Stampede platform as the ''[[MeaningfulName Marie Curie]]''[[note]]the scientist who discovered Radium & died of radiation poisoning[[/note]], almost everyone now believes that to be the name of the ship, despite being officially unnamed.
* CreatorBreakdown: The reason for the fic's massive ScheduleSlip.
* CurbStompBattle: In ''Cry of the Falcon'', the [[spoiler: Earth Alliance commando unit attacking Siegel and Lacus Clyne]] is assisted by a half-dozen [[HumongousMecha Forbidden]] [[EliteMooks Vortexes]]. Their target is covered solely by [[spoiler: [[SuperPrototype the Justice]]]], with a rusty [[spoiler: [[AcePilot Athrun Zala]]]] at the controls. [[spoiler: The poor bastards never stood a chance.]]
* CustomUniform: Instead of the white coat and uniform worn by ZAFT Commanders, Ken prefers to wear the red uniform and a BadassLongcoat. The Gray Demons have a subtler modification, using feathers on the collar of their uniforms & flightsuits.
* DeadpanSnarker: Ken, as part of the [[TheStoic Stoic]] persona that he uses at the beginning of the fic.
* DeathSeeker: Ken himself, for [[spoiler: designing GENESIS.]] Eventually, [[spoiler: Athrun]] is revealed to be one as well, during [[spoiler: Jachin Due. Both survive, but barely.]]
** Also [[spoiler: Victor Tempest.]]
* DefrostingIceQueen: Ken spends the first half of the series addressed as [[LastNameBasis DiFalco]] or Falcon; as he begins to [[CharacterDevelopment lose his stoicism and form closer bonds with the people around him]], they call him [[FirstNameBasis Ken]].
* TheDeterminator: Heavily discussed in-story; borderline AuthorFilibuster, since it's largely an expression of the author's then-opinion of Kira's canonical tactics--see [[{{Flanderization}} Flanderization]]--but it's still in-character for the person usually saying it, seeing as it's [[WarriorPoet Ken]]. This discussion culminates in [[spoiler: [[FightingYourFriend Ken's duel with Kira at Jachin Due]]; WordOfGod states had the battle not been interrupted, Ken would've been the ultimate victor, due to his [[TheDeterminator determination]] making up for Kira's advantage in pure skill.]]
* DoesNotLikeGuns: Ken, partly as a result of being nearly killed with one in a botched robbery before the series. Ironically, [[spoiler: while he's as pathetic with most firearms as would be expected, he's eventually revealed to be an expert sniper.]]
* TheDreaded: To some extent, several of the top [[AcePilot aces]] of the old True ZAFT. An example on the Earth Alliance front appears to be Major [[BadAssNormal Karen Willet]], who shut up and cowed even trigger-happy [[ImperialStormtrooperMarksmanshipAcademy Oscar]] [[NukeEm Goldberg]] just by showing up and uttering a few harsh words.
* DrivesLikeCrazy: Ken, as noted once in ''Birds of a Feather'' and then referenced again when his subordinates refuse to let him drive during the escape from [[spoiler: the attack on Section Nine's Orb headquarters in ''Cry of the Falcon''.]]
* EasyLogistics: Subverted. Despite having their own warship construction facilities, True ZAFT still has to raid Earth Forces convoys to stay supplied.
* ExpandedUniverse: A few authors have played with the Falconverse setting and certain elements have been canonized:
** [[http://www.fanfiction.net/s/3299267/1/Cry_of_the_Falcon Cry Of the Falcon]]. Solid Shark's sequel to [=BoaF=], covering the events of the Destiny period.
** [[http://www.fanfiction.net/s/3636180/1/Soldier_of_ZAFT Soldier of ZAFT]]. A prequel to [=BoaF=], intended to cover Ken's time in ZAFT, leading up to [=BoaF=]. It's on the back burner while [=CotF=] is being worked on, but the author intends to complete it.
** [[http://www.fanfiction.net/s/3055565/1/Rebellion Rebellion]], by Ominae. Set in the interquel period between SEED and Destiny (Or rather, Birds of a Feather and Cry of the Falcon), detailing a rebellion within the Equatorial Union against the EA leadership. Canonized in broad strokes.
*** That story is only slightly connected to the Falconverse as far as its own continuity is concerned. The only Falconverse element to appear is Ken's sister Sophia. In the Falconverse, ''Rebellion'' is -with broad strokes- canon, but within ''Rebellion'' the Falconverse isn't quite that connected although it is.
** [[http://www.fanfiction.net/s/3714582/1/Beware_the_Left_Eye Beware The Left Eye]], by Wild Goose. A pair of sidestories focused on [=CotF=] side character Saito, with shoutouts to Full Metal Jacket and Ghost in the Shell. Considered fully-compliant with Falconverse canon.
** [[http://www.fanfiction.net/s/3863677/1/March_to_the_Future March to the Future]], an AU Time Travel fic by Wild Goose, featuring characters from ''Beware The Left Eye'' as [[ShellShockedVeteran Shell Shocked Veterans]] thrown back to the start of [=BoaF=] by a freak accident, and [[TrappedInThepast trying to survive the past]] while trying to keep the plot from running off the rails.
** [[http://www.fanfiction.net/s/3805496/1/Owaru_Day_by_Day Owaru Day by Day]] by Ominae. It's a fic based on Richard Yamato Chung, Kira's Japanese-Chinese-Filipino cousin after he was recruited by Ken in Section 9. He gets more action for a while than in some of the chapters in BOAF, leading some of the S9 officers after Orban special forces launch the initial attack on S9 headquarters. [[ShoutOut Even the infiltration stage of the commandos is based on the End of Evangelion when JSSDF commandos launch a raid on NERV headquarters.]] The author admits that he got carried away with the character crossovers.
* {{Expy}}: Ken's MidSeasonUpgrade, the Preybird, is an expy of the Gundam X.
** In ''Cry of the Falcon'', the Earth Alliance's Project Zeta brings forth the [[LightningBruiser Zeta]], [[NukeEm Nova]] and [[{{BFG}} Sigma]] - expies of the [[Anime/MobileSuitZetaGundam Zeta]], [[MobileSuitGundam0083StardustMemory GP02]], and [[GundamF91 F91]].
** Also in the same fic, Earth Forces pilots [[VideoGame/AceCombat Allen C. Hamilton]] and [[{{Hellsing}} Luc Bernadotte]]
** In the same fic, ZAFT drops the DOM and goes instead for the TRVF-51 Fianna, which is the SV-51 of MacrossZero.
** Ken himself is also a partial expy of the Honorverse's [[{{Determinator}} Victor Cachat]], whose signature traits ended up defining the final version of Ken (who went through several incarnations in the planning stages of the fic, and was not originally envisioned as military at all).
** In ''Cry of the Falcon'', Jonas Pike and Oscar Goldberg's interactions are evocative of longsuffering [[StraightMan Krindi Fain]] and aiming-impaired [[BoisterousBruiser Erkum Pol]] from the ''Literature/PrinceRoger'' series. (Though Goldberg's a lot more eloquent than Erkum ever was.)
* EyepatchOfPower: Ken. In ''Beware the Left Eye'' and ''March to the Future'', Saito.
* FalseFlagOperation: [[spoiler: an Earth Forces commando team]] attempts to assassinate Siegel & Lacus Clyne using Section Nine weapons in ''Cry of the Falcon''. They fail.
* FixFic: ''Cry of the Falcon'' appears to be giving ''Destiny'' this treatment.
** WordOfGod states the intent is to salvage the potential the author saw in the ''Destiny'' plotline, believing there was still ''something'' worthwhile about the premise -- TheyWastedAPerfectlyGoodPlot.
* [[{{Flanderization}} Flanderization]]: Of Kira's so-called ThouShaltNotKill policy. It was only long after completing ''Birds of a Feather'' that the author realized he'd misinterpreted Kira's preference for disabling attacks for an unwillingness to kill, when in fact Kira does not hesitate to do so even after acquiring the Freedom, when the need arises.
* GamebreakingInjury: [[spoiler: As a result of the wounds he suffered at Endymion, Ken has an artificial heart and lung, powered by his body's bioelectric field. While adequate for normal activity, it proves insufficient for strenuous activity, resulting in Ken's tendency to connect his prosthetics to a portable battery supply or his mobile suit's power system when going into combat. His [[{{Pride}} preference not to mention the vulnerability to anyone]] nearly kills him more than once.]]
* {{Gorn}}: The [[spoiler: siege of the Section Nine Orb base]] is considerably bloodier than anything else in the Falconverse, and frequently touches on this trope.
* GeneralFailure: Several, for the Earth Forces, in ''Cry of the Falcon''. They tend to be [[YouHaveFailedMe removed from service]] after their incompetence becomes obvious.
** Zig-zagged with Admiral Chernock: he led the 4th Fleet in the attempt to blockade the PLANTs, was scapegoated for the subsequent defeat and spent ''Birds of a Feather'' on a beach in Mexico. He's rehabilitated and returned to active duty in ''Cry of the Falcon.''
* GratuitousGerman: The inscriptions on the Gray Demons' swords are all in German, albeit probably with atrocious grammar, being the product of online translator programs. (The author originally wanted [[Literature/TheLordOfTheRings Elvish]], but was unable to find translations for many of the required words.)
* GrayAndGrayMorality: While the author considers ZAFT to hold the moral high ground, the Earth Alliance and ZAFT are portrayed as having both [[MyCountryRightOrWrong dedicated soldiers fighting for their country]] ''and'' bad guys. By the endgame, both sides have abandoned all claim to the moral high ground.
** As an example, [[spoiler: the Earth Forces assassination team in Cry of the Falcon]] have no problems with assassinating a former head of state and his daughter, but draw the line at killing children, even if it risks blowing their FalseFlagOperation.
* HalfTheManHeUsedToBe: [[spoiler: Tolle Koenig's eventual fate.]] Also, [[spoiler: [[MadScientist Heinrich Metzinger]], on underestimating his creation's dedication to his own purposes.]]
* HeelFaceTurn: In ''Cry of the Falcon'', [[spoiler: none other than Rau Le Creuset.]]
* HeroicBSOD: [[spoiler: Ken experiences one after he fails to shoot down the Moebius carrying the nuke that destroys [[DoomedHometown Junius Seven]] ]].
* HeroicSacrifice: [[spoiler: ''Arkbird'' rams Jachin Due, ZAFT's defense HQ, in an attempt to prevent GENESIS from firing. Tragically, it doesn't work.]]
* HesBack: [[spoiler: Athrun Zala]], in the aforementioned CurbStompBattle.
* HesJustHiding: [[spoiler: Admiral Halberton.]]
* ICallItVera: The swords wielded by the Gray Demons and veterans thereof.
* IHaveNoSon: [[spoiler: Patrick Zala says almost the exact words to Athrun at Jachin Due. Them being almost the last words Athrun hears from his father probably contributed to his subsequent attempt at [[HeroicSacrifice blowing]] [[DeathSeeker himself]] [[TakingYouWithMe up with Le Creuset]].]]
** Also [[spoiler: Rear Admiral Charles Kreitzman of the Earth Forces, in reference to his Coordinator son. This eventually leads to his death, when the embittered son [[RammingAlwaysWorks rams]] his ship into the father's at Mendel.]]
* ImperialStormtrooperMarksmanshipAcademy: Oscar Goldberg, the pilot given the machine with a nuclear bazooka because he couldn't hit the Moon if he was standing on it with anything smaller.
* ImplausibleFencingPowers: Just about anyone with a sword in this 'verse, but most notably Ken himself. Attempts are made to justify his deflecting bullets in-story--at the least, his sword would survive, due to being made of a material usually used for ''[[HumongousMecha mobile suit]]'' weapons--but the author fully acknowledges it's mostly RuleOfCool.
* LaserGuidedTykebomb: Victor Tempest aka Huckebein the Raven, is brought back to life for the express purpose of killing Ken.
* MarthDebutedInSmashBros: Some reviewers thought that Sigma's Variable Speed Beam Rifles were inspired by VARIS ammunition from ''CodeGeass'', not realising that the [[GundamF91 F91]] made its debut in 1993.
* TheMentor: Ken to Kira, before the latter begins to surpass the former and their opinions on tactics diverge significantly.
* MentorOccupationalHazard: [[spoiler: Very nearly inflicted on Ken by Kira himself.]]
* TheMole: Section Nine has one, leaking very important information to the Earth Forces. We just don't know who it is yet.
* MyCountryRightOrWrong: A major theme of the [[TheVerse Falconverse]] as a whole. Of the major characters, many struggle with the implications of remaining loyal to nations whose actions become increasingly extreme. Some decide all they can do is fight as honorably as they can themselves, while others abandon their previous allegiances entirely. A handful in between decide loyalty to the military is not the same as loyalty to the nation said military protects, and take the view that they can best protect the nation by breaking with the military. Such a viewpoint is, in fact, what kicks off the entire story.
* MyGreatestFailure: In the [[{{Backstory}} backstory]], Ken was in a position to [[spoiler: shoot down the Mobius carrying the nuclear missile that destroyed [[DoomedHometown Junius Seven]], and missed.]] This, of course, led directly to the next candidate for his greatest failure, in which his efforts to prevent a repeat of the situation ended with him [[spoiler: handing a WaveMotionGun capable of [[EarthShatteringKaboom frying most of Earth's surface]] to [[OmnicidalManiac Patrick]] [[RevengeBeforeReason Zala]].]]
* [[NiceJobBreakingItHero Nice Job Breaking It, Hero]]: When you get right down to it, almost every single problem [[spoiler: Ken]] has was his own fault. [[spoiler: He deserted ZAFT after accidentally creating a WaveMotionGun capable of [[EarthShatteringKaboom destroying the Earth]], suffered severe injury from his former subordinate Victor Tempest out of [[HonorBeforeReason a misplaced desire to finish the poor bastard "honorably"]], and almost got himself killed and his mission catastrophically failed through his unwillingness to talk things over with Kira.]] And, as if that weren't enough, [[spoiler: creating the weapon to rectify the first mistake resulted in an arms race that, as of the sequel, has pretty much destroyed the technological advantages that allowed his small group to be so effective.]] Oops.
* NoSenseOfDirection: Having been born in space, with little time spent on Earth, Ken is almost incapable of navigating on planet in daylight without computer assistance. This [[spoiler: leads directly to the fic's version of Cagalli's first meeting with Athrun, as she has the bad luck of being in Ken's mobile suit when it takes damage to its navigational systems in the middle of the Indian Ocean.]]
* NotQuiteDead: [[spoiler: Nicol Amalfi, Aisha.]]
* NuclearWeaponsTaboo: Averted. [[spoiler: The Earth Alliance regains nuclear capability even earlier than canon, and isn't shy about using them.]]
* NukeEm: A favored tactic of the Earth Alliance. It gets progressively less effective as the storyline progresses, however, and [[spoiler: nearly gets Muruta Azrael removed by his own allies when he overuses the nuclear option.]] It ''does'' eventually get his successor [[spoiler: [[BoomHeadshot executed]],]] after a particularly spectacular failure.
* OmniscientMoralityLicense: Ken displays this at times, mostly due to his towering confidence in his own intelligence and ability. It typically does not go well, having cost him a career, almost a planet, and nearly his own life several times over.
* PaperThinDisguise: [[spoiler: Ken uses a gasmask & voice modulator to hide his identity in ''Cry of the Falcon''. People close to him see through it, while it works well enough for strangers]].
* PoorCommunicationKills: [[spoiler: Ken's trust issues and willingness to [[IDidWhatIHadToDo use drastic methods]] eventually results in a near-fatal duel between Ken and [[MartialPacifist Kira]]. Circumstances intervene and they reconcile, though they never entirely agree on methods.]]
** Also occurs just after Operation Spit Break, when [[spoiler: damage to Preybird cuts the connection between its reactor and Ken's artificial heart (see GamebreakingInjury). Not having informed the ''Archangel'' crew of the infirmity, he goes into cardiac arrest and nearly dies before someone who ''does'' know arrives to assist.]]
* [[{{Pride}} Pride]]: Along with [[{{Revenge}} Revenge]], this particular character flaw is responsible for most of the big problems of the story.
* RammingAlwaysWorks: Twice. First, [[spoiler: ZAFT Captain Kreitzman rams his ship into Earth Forces Admiral Kreitzman's flagship at Mendel.]] More prominently, [[spoiler: Lance "Sparky" Cooper and his crew smash the ''Arkbird'' into Jachin Due during the GrandFinale.]]
* RedBaron: Ken is known as the Butcher Bird to the Earth Forces. More commonly, though, he's known as the Grimaldi Falcon, after the battlefield where he first became widely known.
** In Cry of the Falcon, apart from being hailed as ZAFT's [[Literature/LordOfTheRings Broken Blade]], the Earth Forces proclaim Ken to be the [[VideoGame/AceCombat Demon Lord]].
*** The author considers the section of the story wherein Ken is first dubbed "Broken Blade" to be something of an OldShame; he was reading Literature/TheLordOfTheRings at the time, and allowed it to influence his writing to a degree he now wishes it hadn't.
* {{Retcon}}: No, [[spoiler: Kira and Cagalli are ''not'' related to each other]]. [[{{OTP}} Why do you ask?]]
** A retcon that caused the author to nearly tear his hair out several times, and finally resulted in him having a character with the requisite knowledge ''state outright'' that [[spoiler: Kira and Cagalli ''were not related''.]] A reviewer of some note promptly assumed the author was, rather than attempting to put an end to controversy, trying to be sneaky.
*** To be fair, there's a certain degree of IncestSubtext in early interactions between Kira and Cagalli in canon, before the SquickTease revalation that they were related. One wonders if this influenced the writers of Series/KamenRiderDenO and Series/KamenRiderDouble, both which featured significant ShipTease that turned into SquickTease at the reveal of blood relationships. Though there are some who [[IncestSubtext don't care the characters are related]]...
* TheRevolutionWillNotBeVillified: Essentially the entire point of Ken [=DiFalco=]'s existence. This is the defining aspect of his character, and ''keeping'' the Revolution like this causes his desertion and everything that follows from it.
* TheRival: Victor Tempest in the first story, Neo Roanoke, and Karen Willet in the second.
* RoyalsWhoActuallyDoSomething: Rather than the brief, fairly unimportant piloting opportunity she gets in canon, here Cagalli enters the fight as early as the Desert arc, acting as Ken's gunner during the battles against the Waltfeld team. Moreover, she gets her own mobile suit much earlier, acquiring the Strike Rouge in time for the Earth Alliance attack on Orb.
* RuleOfFunny: The riotous, eye-damaging combination of colors chosen by Oscar Goldberg for his [[{{Gundam0083}} No]][[NukeEm va]], inspired by an [[HumongousMecha [=AC=]]] design from VideoGame/ArmoredCore that the author once came across.
* RunningGag: Any time Ken enters combat outside of his [[HumongousMecha mobile suit]], he ''will'' get shot. Also, in ''Cry of the Falcon'', he never gets to use his new rifle very long; it's always destroyed almost as soon as the battle begins.
** Another example crosses with BlackComedy: the Earth Alliance's [[FourIsDeath Fourth Fleet]] has been destroyed twice while attempting to carry out nuclear attacks on the [=PLANTs=], and the Atlantic Federation's Fourth Fleet was the one humiliated in the Blockade, as shown in ''Soldier of ZAFT''.
** Ken has a tendency toward long-winded speeches. This is not a gag by itself, but rather the frequent [[LampshadeHanging lampshading]] by other characters and his own obliviousness any time someone points it out.
* ScheduleSlip: Once updated frequently, as of this edit over two years have passed since a chapter was published. WordOfGod is that a CreatorBreakdown is responsible, and that updates are fully intended to resume once the author's situation stabilizes.
* ShadowArchetype: Neo Roanoke's GAT-X505 Nightwing is a dark copy of Ken DiFalco's ZGMF-X00A Preybird, and Karen Willet's GAT-X510 Reaver is a copy of Kira Yamato's ZGMF-X10A Freedom.
* ShipTease: Early in ''Birds of a Feather'', between [[spoiler: Ken]] and [[spoiler: [[BridgeBunnies Miriallia Haw]]]]. The former, being largely [[ObliviousToLove oblivious]] doesn't even notice until it's pointed out later. Ironically, the latter gets caught up in an assassination attempt on someone else in the sequel due to having come back to Orb for the former's wedding to [[spoiler: [[TheCaptain Murrue Ramius]].]]
* ShootTheHostage: [[spoiler: When an enemy captures Ken and Preybird just before 2nd Jachin, Ken tells Kira to shoot him and kill the enemy; Kira decides to TakeAThirdOption. While everyone goes home safely, Ken believes that Kira doesn't have the resolve to see events to their conclusion, and Kira believes that Ken's become a KillEmAll fanatic. The fallout from this directly leads into their abortive duel at Jachin.]]
* ShoutOut: Many to [[VideoGame/AceCombat the Ace Combat series]]:
** The Gray Demons are inspired by the Demons of Razgriz, from Ace Combat 5.
** The prototype for the ''Eternal'' is named ''Arkbird''.
** Victor Tempest's alias, "Huckebein the Raven", shared by Wolfgang Buchner/Peter Beagle, the OldMaster of Ace Combat 5.
*** Actually somewhat accidental; the author originally intended to call him Huckebein the ''Vulture'', but forgot when actually writing the character's introduction.
** In ''Cry of the Falcon'', Ken's first callsign? Moebius One. Later, he's tagged by Hamilton as the Demon Lord. Both were considered the best pilots of their respective Ace Combat games (04 & Zero).
** When Halberton and Ken meet prior to the Orbit Battle, they remind each other that '' "There is only one rule in war: Survive."'' This was Ace Combat Zero's tagline.
** In ''Cry of the Falcon'', one of Ken's former ZAFT teammates begins her story by saying "[[VideoGame/AceCombatZeroTheBelkanWar It was a cold and snowy day]]."
** Ken frequently refers to the [=PLANTs=] as "The Homeland" and to "The Revolution", ideals close to the heart of one [[Literature/HonorHarrington Victor Cachat.]]
*** "The Homeland" is actually used in canon several times, particularly early in the series.
** Ken destroys GENESIS by [[AirstrikeImpossible flying inside the satellite]] and blasting it with Preybird's antimattor cannon, an homage to the penultimate stages of various Ace Combat games.
** [[spoiler: The epilogue also contains major shoutouts to GhostInTheShell, most notably Section Nine and the title of "Major".]]
** [[spoiler: Millenia Crescent in ''Cry of the Falcon'' has a prosthetic body due to crash injuries, had trouble adjusting to her body at first, is 99 percent machine, and has purple hair and amber eyes]].
** Section Nine's primary small arms supplier is [[GhostInTheShell Seburo]].
** Ken's repeated statement that surprise is achieved by the commander's misinterpretation of data could well be considered Literature/HonorHarrington's catchphrase.
** Construction of an ''enormous'' sandwich as a ''light snack''; a shoutout to a similar scene in ''Miss Midshipwoman Harrington'', Honor's LowerDeckEpisode in the ''Changer of Worlds'' anthology.
** The "Falcon's Lessons of War" frequently quoted in ''Birds of a Feather'' were inspired by remarks made by Kevin Usher in the ''Literature/HonorHarrington'' short story ''From the Highlands'', and many of the lessons themselves are shoutouts to various other sources.
** The [[spoiler: ''Odin's'']] emblem is a direct reference to FinalFantasyVIII.
** The name of Ken's sword, [[spoiler: [[MeaningfulName Griever]]]], is another reference to the above RPG.
** The Shiva Option is a nod to the third of the ''Starfire'' books.
** The [[RedBaron nickname]] and eventual ship name ''Asmodeus'', in addition to the obvious demonic reference, is specifically a ShoutOut to a perhaps obscure fantasy novel called ''Ariel'', which is where the author originally came across the name.
** ''Cry of the Falcon'' reveals Ken's personal swordsmanship style to be of the [[FateStayNight Ganryu School]].
** The [[spoiler: program that created Ken in the first place was a clumsy ShoutOut to ''VideoGame/MetalGearSolid''.]]
** Nick "Red Lightning" Drallig of ''Soldier of ZAFT'' is a dual ShoutOut to Crim the Red Lightning of ''Anime/DotHackSign'' and [[Franchise/StarWars Jedi Master Cin Drallig]].
** The Frighteners are named after a group in [[VideoGame/ArmoredCore Armored Core 2]].
** The commanding officer of the ''[[spoiler: Odin]]'' is named [[SyphonFilter Jason Chance]], though he doesn't share his namesake's treacherous nature.
** Several Earth Alliance flag officers in ''Cry of the Falcon'' are named after extras in the Starfire and Literature/EmpireFromTheAshes books, and Wing Commander games.
* SpannerInTheWorks: Ken recognises the ''Archangel'' crew's potential to be this and works to add them to the plan, as well as recruiting them. True ZAFT and Shiva Option Three are intended to be this to the Earth Forces and mainline ZAFT. [[spoiler: Kira is also nearly this to Ken's plans.]]
* ShroudedInMyth: Ken's master Sasaki Kojirou, who uses an obvious pseudonym and appears to be more than meets the eye. His only explanation: ''"I wasn't always a ronin."''
* SuperPrototype: Subverted. [[spoiler: Ken is a pseudo-prototype of the Ultimate Coordinator project, born of the artificial womb as part of a related project with differing goals. As ''Cry of the Falcon'' reveals, however, he's degenerating on the genetic level, and was not expected to reach adulthood; he's beaten the odds, but will never be as effective as he once was, and continues to slowly slip behind the capabilities of the "final product", Kira.]]
* SuspiciouslySpecificDenial: In early chapters, Ken's adoptive sister Sophia, an Earth Forces officer, repeatedly stresses that she has no ''space'' combat experience. [[spoiler: She's an ''atmospheric'' jet fighter ace; when the ''Archangel'' breaks out the Skygraspers, Skygrasper 2 becomes Sophia's machine instead of Cagalli's - and she uses it to greater effect]].
** Kind of HilariousInHindsight; the author didn't come up with that particular twist until the chapter in which it was [[TheReveal revealed]]. A case of ThrowItIn that meshed well with established information.
* TakingYouWithMe: [[spoiler: Athrun attempts this with [[OmnicidalManiac Le Creuset]] at Jachin, via nuclear meltdown. Fortunately, allies arrive and [[PowerOfFriendship convince him to retreat and survive]].]]
* TechnicianVersusPerformer: Discussed in-story. Being an Ultimate Coordinator, Kira (Performer) edges out Ken (Technician) in terms of natural ability and raw talent; in terms of training, tactics and experience, the advantage goes to Ken. [[spoiler: Events prove Ken to be the superior pilot, but it's acknowledged that given enough time and experience, Kira will surpass him, blending Technician and Performer traits.]]
* ThemeNaming: Almost anything to do with the Gray Demons will have a name either avian or [[NamesToRunAwayFromReallyFast demonic]] in origin.
* ThereAreNoTherapists: Most of them seem to be on the battlefield; unfortunately, several of them are people who really need therapy themselves. The lack thereof is one of the triggering factors for the entire plot.
* ThereIsNoKillLikeOverkill: Ken's tactical philosophy throughout most of the story. Subsequent events show why taking it to the extreme was a [[NiceJobBreakingItHero Bad Idea]].
* TheVerse: As noted under ExpandedUniverse, ''Birds of a Feather'' has spawned its own series of [[SpinOff spin-offs]], with several authors playing around with some elements of the Falconverse. To date, however, the only ''canonical'' stories are the original, ''[[{{Prequel}} Soldier of ZAFT]]'', ''[[{{Sequel}} Cry of the Falcon]]'', side-story ''Beware the Left Eye'', and a yet-to-be-titled sequel to [=CotF=]. ''Fanfic/MarchToTheFuture'' is set within the canonical universe, but is not itself canonical for [[TrappedInThePast obvious reasons]].
* WarriorPoet: Ken, sometimes to extremes; possibly [[JustifiedTrope Justified]] by the HeroicBSOD he spends most of the first story recovering from. By the time the reader meets Ken, he's not entirely sane, making his forays into philosophy more understandable. Also, they sometimes serve a point, as he's additionally a...
* WarriorTherapist: Several characters, including Ken himself. Sometimes backfires, though; in ''Cry of the Falcon'', he's successfully taken Shinn under his wing--so far, at least--but in ''Birds of a Feather'', the results of espousing a philosophy very different from the person he's talking to are shown [[spoiler: in his duel with Kira at Jachin.]]
* TheWarSequence: The [[spoiler: attack on Section Nine's planetary headquarters]] in ''Cry of the Falcon''. Probably the most violent event in the series thus far, standing out in a 'verse usually focused on the relatively bloodless combat of HumongousMecha battles.
* WhatCouldHaveBeen: In the earliest concepts of the story, Ken was an Atlantic Federation citizen living on Heliopolis as a hacker, whose only connection to the conflict at large was his Earth Forces engineer sister [[spoiler: and having designed GENESIS for ZAFT, as an "intellectual exercise".]]
** In the first draft of the actual published chapters, Cagalli accompanied Ken to the hangar containing his first Gundam, and boarded the ''Archangel'' at Heliopolis; this was scrapped when the author couldn't think of what to do from there.
* WhatTheHellHero: Kira calls out Ken on attacking lightly defended Earth Forces supply convoys; Ken's justification is that [[CombatPragmatist the convoys are soft targets carrying supplies they need]], and that they can't afford to [[LeaveNoWitnesses leave witnesses]]. Kira disagrees.
** This and other events lead to a ''massive'' WhatTheHellHero during [[spoiler: the GrandFinale, leading to an attempt to blow each other to pieces. See PoorCommunicationKills.]]
** A milder event occurs in ''Cry of the Falcon''. [[spoiler: Needing inside information on how Durandal thinks, Ken has Rau's recovered body revived, using him as an advisor. ''Nobody'' is happy with this.]]
* WordOfGod: Occasionally invoked for clarification of plot points. Most notably with the aforementioned {{Retcon}}, [[spoiler: when the author became frustrated over the continued debate by readers as to whether or not Kira and Cagalli were related.]]
* XanatosSpeedChess: Ken spends the entire fic doing this. [[spoiler: [[MagnificentBastard Rau Le Creuset]] reciprocates.]]
* YouHaveFailedMe: As something of a nod to the character's canonical... lack of total competence -at least compared to his predecessor from SEED- this happens to [[spoiler: [[FashionVictimVillain Lord]] [[SmugSnake Djibril]]]] after a particularly spectacular debacle that not only fails to achieve its objective, but actually results in [[spoiler: some of the Earth Forces' own units being ''[[NukeEm nuked]]'' by one of their own weapons.]] Cue [[BoomHeadshot summary execution]].
** SugarWiki/AndTheFandomRejoiced in-universe: Djibril's replacement is a more pragmatic villain who understands her strengths and weaknesses, and gains the respect and willing cooperation of her military forces.