The symbol at the southern edge of the map is an upside-down "Z", the final letter of the Yevon alphabet that is also sometimes used to denote the monster known as Sin. The oval frame is marked with the English alphabet written in Yevon script repeated, although it skips "A", which is also the symbol for Yevon.
Spira's unique fauna composes mainly of fiends, hostile monsters that attack any passerby. Other wildlife include small monkeys, dogs, cats, dolphins, chocobos and shoopufs. Spiran plant species resemble real-world vegetation with three notable exceptions: the magical woods of Macalania, the moon lilies of the Moonflow, and plantlike fiends, such as Ochu and Malboro.
The temple of Yevon dominates Spiran life, spreading its teachings and acting as a benevolent protector of a much diminished world—a world where technological and social progress has stalled for 1000 years. Yet, beneath the surface, unity of the Spiran mainland, distrust and old anger still boil leading one to wonder if the various warring factions wouldn't blow each other to smithereens without Sin's pacifying presence. Only blitzball truly unites the world around a common passion, and annual tournaments are held in Luca, left untouched by Sin's wrath mostly due to the Crusaders' efforts.
Spira uses three alphabets that work like ciphers for the real-world Latin alphabet. The signs around the world are written in Spiran script, as is the writing in blitzball teams' logos, and the text on Auron's keg. Tidus also wields weapons with the text "Guardian" inscribed in Spiran script.
The Yevon script is related to Yu Yevon and the faith of Yevon and is used in temples and inside Sin. Cactuars have their own language with Benzo being the only human interpreter.
Before Yevon became the dominant religion across the land people used to worship a different set of deities, as mentioned in the companion novel Final Fantasy X-2.5 ~Eien no Daishō~. The summoning tradition was alive in Zanarkand, but after its downfall it was adopted by Yevon.
The teachings of Yevon, said to have been left by Zanarkand's leader Yu Yevon to his daughter, Lady Yunalesca, were implemented by Bevelle to maintain order through giving the people hope that Spira may someday be free of Sin should they atone. Until Yuna exposes their lies, the temples teach machina is forbidden, that Sin is a result of humanity's pride and use of machina in the past, and that Sin can only be vanquished when humanity has attained purity and had been cleansed of past sins. Until that promised time would come, only the ritual known as the Final Summoning would provide a reprieve from Sin's terror (referred to as "The Calm").
Yuna and her guardians infiltrate Sin and–destroying each of his aeon hosts–force Yu Yevon to manifest his spiritual energy as corporeal matter, making him vulnerable for the first time in 1000 years. They destroy Yu Yevon and end his control over Spira. This severs the people's faith in Yevon.
Two years later, the moral teachings of Yevon have been revitalized in the form of the New Yevon party under Praetor Baralai. Although technically a splinter group of Yevon, the New Yevon party is not a religion, but a way of life, their motto and position on Spira's advancement being "one thing at a time". A rival faction has emerged, the Youth League led by Meyvn Nooj, and their rivalry harbors conflict in Spira until they are unified after the Vegnagun crisis.
In Final Fantasy X, the people of Spira follow the teachings of Yevon. A practitioner of the Yevon faith is referred to as a Yevonite. The faith is named after Yu Yevon, a summoner who lived in Zanarkand one thousand years ago.
Nearly all the peoples of Spira follow the teachings of Yevon, including the Ronso and the Guado. The Al Bhed are an exception and are viewed as heretics by the autocracy for their use of machina, a practice forbidden by the church. As for the Hypello, whether they follow Yevon's teachings is never explored.
Yevon draws inspiration from real-world religions, such as Shintoism (practices and temples), Buddhism (iconography and ritualistic disciplines), Islam (pilgrimages) and Catholicism (hierarchical structure and rigid doctrine). The teachings of Yevon give meaning to people's lives in the face of death, and what Director Yoshinori Kitase tried to show in Final Fantasy X was how people behave in the face of unavoidable fate.
One thousand years ago a great war that became known as the Machina War was fought between the cities of Zanarkand and Bevelle. Yevon, Zanarkand's ruler, saw his people were unable to defeat Bevelle's machina, and was unwilling to allow his city to be swallowed up into history. He devised a plan to preserve its memory for all eternity, even if he could not save the city itself.
At Yevon's order, most of the surviving citizens of Zanarkand gave up their lives to become fayth whom Yevon could use to conjure a summoned Zanarkand based on the memories of its citizens. The summoned replica was to be a utopia removed from conflict. Yevon manifested the city out at sea in an undisclosed location, far removed from the Spiran mainland and the warmongering Bevelle. To prevent anyone from easily locating his summoned city of memories, Yevon used magic to surround himself with disembodied spiritual energy, called pyreflies, to create an armor, which would become known as the monster Sin; this armor would protect him while he summons the dream Zanarkand. Sin would attack areas with high populations and advanced technology bringing technological progress to a halt and keeping the people on the mainland from giving much thought to what may lay far out at sea.
Maintaining his summoned city and creating Sin was a greater strain than Yu Yevon's human form could handle, and his humanity faded, leaving only his instincts to maintain Dream Zanarkand. Thus Sin's first act as an instinctual beast was to destroy the original Zanarkand.
Yevon had a daughter, Lady Yunalesca, who was the first summoner to defeat Sin with a technique known as the Final Summoning. Afterward she would remain in Zanarkand as an unsent to grant the gift of Final Aeon to summoners who complete their pilgrimage. The Final Aeon is an ultimate summon and it is different for each summoner, because a Final Aeon must be someone to whom a summoner has a powerful bond, such as a friend, sibling, or spouse. Thus, a summoner's guardian is chosen to become the fayth for that summoner's Final Aeon.
The Final Summoning can destroy Sin due to the bond that unites the aeon and the summoner, but Yu Yevon endures the destruction of its vessel, merges with the Final Aeon, and uses it as the core of a new Sin. Yu Yevon's merge with a Final Aeon kills the summoner.
With Sin's "defeat", a short period of peace settled on Spira, known as the First Calm. The survivors began reconstructing Spira, focusing on Bevelle. Yu Yevon regenerated Sin using Zaon's aeon, Yunalesca's husband whom she had made into a fayth, as a core, and Spira's plight began anew. The new Sin destroyed the remaining machina civilizations and thus machina use began to fall out of favor.
Maechen speculates that motivated by her desire to protect Spira from Sin, Yunalesca had agreed to provide a means to temporarily dispose of Sin in return for her father to be honored. However, according to the Final Fantasy X Ultimania Omega Yunalesca did not have a direct hand in creating the Yevon religion or its doctrine, and only learned of Yevon's teachings via the people who would visit her at the Zanarkand Dome seeking the Final Aeon. Nevertheless, many fayth were placed in the temples of Yevon for the summoners to follow in Yunalesca's footsteps in defeating Sin. Yevon proclaims that the Final Summoning can defeat Sin for a time and give Spira hope, but states that unless the world embraces the teachings of Yevon and atones for its sins, Sin will never go away.
Seizing public sentiment after Sin's first return, the temples took control of Spira with the main temple being situated in Bevelle. Ever since the Final Summoning has played an invaluable role in the teachings of Yevon. Even if Bevelle had not been a center for summoning practice, summoning would become one of its core dogmas as the teachings revolve around the Final Summoning and the ban on machina; it was Yevon's wish that there should never be technological convenience that would allow for Dream Zanarkand to be discovered or its summoning be halted. As told in Final Fantasy X-2.5 ~Eien no Daishō~, the Al Bhed (then known as the "Bedore") were used as scapegoats for the emergence of Sin as they had worked in the factories that had produced weapons for the Machina War. After Yevon arose as the main religion across the land many Bedore were hunted down and executed, and Yevon had a hand in changing their name from Bedore to Al Bhed. Al Bhed were thus cast out from society.
Over time Bevelle set up temples throughout Spira placing a fayth in each one. Some of the fayth originate from a time before Sin, but others were created by the temples themselves for the purpose of perpetuating the doctrine concerning the Final Summoning and the pilgrimage summoners must undertake to qualify. To govern these laws, Yevon came to be with four Maesters at the top, a high priest for each temple, and many other priests, monks, and nuns.
Fayth unceasingly sing a hymn that was reported to have been heard emanating from the fayth on Mt. Gagazet at Sin's first public appearance—a hymn which later became known as the "Hymn of the Fayth". Around the time Bevelle adopted the teachings the song was taken up by those who were in defiance of Bevelle, the Al Bhed in particular. At first, Bevelle prohibited the use of the song, but soon spread a story it was sung to soothe the souls of the dead. The hymn was incorporated into the teachings of Yevon thereafter and regarded as a holy song.
Although the temples' teachings had become widespread, 600 years passed with no one able to defeat Sin. During that time many doubted Yevon's teachings, the priest Omega among them, who was executed for openly rebelling against the temples. Unable to go to the Farplane, his spirit lingered in Spira, and Omega became a fearsome fiend.
Six hundred years after the temple was established a summoner named Gandof defeated Sin, tearing the Calm Lands asunder and isolating the Remiem Temple, thus creating the Second Calm and becoming the first high summoner. Gandof suffered the same fate as Yunalesca had and died. This gave credence to Yevon's teachings, and doubts about the temples subsided. As before, the calm was short-lived and Yu Yevon rebuilt Sin, which started its rampage anew as the third Sin appeared publicly with Gandof's Final Aeon as its core. Gandof was posthumously titled "high summoner", a title which would from then on be bestowed on those who had defeated Sin. Statues of Gandof were placed in Spira's temples and his story was told as an example of honor and sacrifice to be followed.
Summoner Yuna sets out on her pilgrimage, but becomes labeled a heretic when she kills Maester Seymour Guado after confronting him for the murder of his father and he turns on her. Yuna is put on trial during which she learns that high-ranked priests of Yevon lost faith and hope of defeating Sin long ago, and that the Grand Maester himself is an unsent. Maester Kelk becomes disillusioned with Yevon and departs, and the now-unsent Seymour Guado kills Wen Kinoc to absorb his pyreflies and grow stronger.
After escaping her predicament in Bevelle, Yuna resolves to continue her pilgrimage regardless, as it is the fayth who grant the summoner their powers, not the temples. Kelk grants her passage onto Mt. Gagazet, but is soon killed by Seymour who is still gathering more power. When Seymour confronts Yuna's party, however, they defeat him again and he soon absorbed by Sin.
Upon reaching Zanarkand and learning that Sin's rebirth is certain, Yuna declares Final Summoning a false rite that only perpetuates Spira's suffering. Yunalesca attempts to kill Yuna and her guardians to "release them" now that they have learned the truth behind Yevon and rejected it, but Yuna and her guardians prevail and kill Yunalesca, ending the practice of Final Summoning.
They are called back to Bevelle to meet Grand Maester Yo Mika. By this time, possibly as a result of its Maesters being gone, Yevon is in a state of decay and chaos. Mika urges Yuna to summon her Final Aeon, but she explains they have obliterated Yunalesca, and thus broken the very practice Yevon stands for. Mika is overcome by despair of the thought of Yevon being made obsolete and Spirans succumbing to despair as a result, and departs for the Farplane.
Yuna and her guardians enter Sin on their airship and kill Yu Yevon at its core, ending his summoning of Sin and Dream Zanarkand. The fayth he had used for his summoning, as well as the fayth in the temples, are released, and their souls depart for the Farplane. With no more fayth left in Spira, the summoners are unable to call forth aeons, and with the Maesters of Yevon now dead, and the temples' hypocrisy revealed to all of Spira, Yevon is disbanded.
Two years later, in Final Fantasy X-2, the moral teachings of Yevon have been revitalized in the form of the New Yevon party under Praetor Baralai. Although technically a splinter group of Yevon, New Yevon is not a religion, but a way of life, their motto and position on technological advancement being, "one thing at a time".
Mythology The concepts of magic, spiritual energy, the power of memories, and the faith of the people are influential in the world of Spira, including sporting events, religious practices, the technology, and even in some of the native wildlife. The themes and concepts, to name a few, cover pyreflies and their relation with death, aeons, the fayth, Sin and the teachings of Yevon.
Aeons are the physical realization of the fayth's dreams. The fayth communicate with summoners who pray to them within the Chamber of the Fayth, and establish a mental link between the fayth and the summoner. Using this link, the fayth gives their dream a physical form: an aeon. Aeons are powerful creatures only a summoner can use in battle. Most aeons resemble their respective fayth, so it can be assumed the aeon takes on aspects of the person whose soul is sealed inside the fayth statue.
Many summoners can communicate with any one fayth to establish a mental link with them, enabling them to then summon the fayth's aeon, but only one summoner can call on a particular fayth's power at any one time. This is why during the aeon duels two of the same aeon cannot battle one another. (The Dark Aeons are an exception.)
The fayth are likely the aeons themselves, or otherwise are in control of them, as evidenced when Bahamut's fayth encourages Yuna to call the aeons in her battle with Yu Yevon, saying: "Promise me you'll call us?" and "We aeons...call us!!". This is further supported by the connection between Seymour's mother and her aeon, Anima.
The aeons give the summoner the undying loyalty for one thing in return: to stop dreaming and be at peace with the final destruction of Sin. However, if the summoner summons the Final Aeon to vanquish Sin, Yu Yevon at its core possesses the Final Aeon, killing the summoner, and turns the Final Aeon into a new Sin, perpetuating an endless cycle.
Yuna's pilgrimage takes her through Luca where fiends invade the blitzball stadium during the tournament final, and Maester Seymour summons Anima to destroy them. Yuna and the crowd are in awe, and Yuna comments on Seymour's aeon's power. On the Mi'ihen Highroad Yuna runs into Belgemine, a summoner who has dedicated her life in honing other summoners' skills in preparation for their final battle against Sin. She challenges Yuna to a duel of aeons.
The party eventually discovers Seymour had murdered his father to succeed him as maester, and when they confront him Seymour summons Anima to vanquish them. Yuna has just obtained Shiva from the Macalania Temple and prevails and Seymour is killed. Yuna is unable to send him and he becomes an unsent. During their escape from the temple Yuna and her guardians run into Sin who whisks them away to Bikanel desert where they find the hidden Al Bhed town of Home and the summoners the Al Bhed had kidnapped to stop their pilgrimage. As Home is attacked, the summoners fend off the invaders by summoning aeons, but in the end the town is obliterated.
Yuna is being forced to marry Seymour in Bevelle, but she feigns to commit suicide and jumps off the cathedral tower. She summons Valefor mid-air who flies Yuna to the Bevelle Temple where she obtains Bahamut. Yuna and her guardians are arrested for aggression toward a maester, and banished to the dungeons below Bevelle. They escape, but Yuna must battle a fellow summoner, Isaaru, in a contest of aeons, though she emerges victorious.
Yuna runs into Belgemine again for another aeon duel in the Calm Lands, and finds the hidden aeon Yojimbo from the Cavern of the Stolen Fayth. The hidden Remiem Temple is only accessed on a chocobo where Yuna discovers Belgemine is an unsent, and obtains the ultimate aeon, Magus Sisters. On the Al Bhed's airship, the Fahrenheit, the party finds Baaj where Seymour had sealed Anima's fayth, and Yuna obtains her as an aeon.
In Zanarkand Yuna discovers one of her guardians must be made a fayth for her personal Final Aeon. Should their bond be strong enough, the Final Aeon could destroy Sin, but Yu Yevon at its core would survive and make the Final Aeon into a new Sin. Yuna doesn't want to perpetuate Spira's suffering in this manner and discards Final Summoning as a false rite. Instead, the party decides to invade Sin's innards with the airship to destroy Yu Yevon directly. Yuna can visit the temples of Yevon to speak to the fayth, and Bahamut's fayth urges Yuna to call on the aeons for the final battle.
Inside Sin the party destroys Braska's Final Aeon, freeing Yu Yevon, who one by one possesses Yuna's aeons whom she must then destroy. With all the aeons killed Yu Yevon has nowhere to hide, and the party destroys him for good. Sin explodes on the skies of Spira and the fayth can finally rest. Their souls depart the fayth statues to the Farplane and aeons disappear from Spira.
After the onset of the Eternal Calm summoners can no longer call forth aeons. The unsent spirit Shuyin possesses the fayth on the Farplane and sends their aeons to Spira to attack the temples. Yuna vanquishes them one by one, and at the end of her quest sends Shuyin to his final rest.
The fayth of Besaid Temple is a small girl. Valefor has high evasion and speed, but only mediocre attack power, though this changes later in the game. Valefor can deal non-elemental damage and cause a turn delay with her special attack, Sonic Wings, and with her two Overdrives, the default Energy Ray and the more powerful Energy Blast. Valefor is the only aeon to have two Overdrives, and is revived after 8 battles should she die.
Energy Blast is obtained by speaking to a girl and her dog in Besaid Village. To break the damage limit, Yuna must have obtained her Nirvana, and power it up with the Moon Crest. Later in the game Valefor is so fast that if Sonic Wings is used repeatedly against a single opponent, they never have an opportunity to attack. Because Valefor is a flying aeon, some enemies cannot hit her at all due to their attacks only hitting ground targets (an example being Omega Ruins' Demonolith). The fayth of Besaid Temple is a small girl. Valefor has high evasion and speed, but only mediocre attack power, though this changes later in the game. Valefor can deal non-elemental damage and cause a turn delay with her special attack, Sonic Wings, and with her two Overdrives, the default Energy Ray and the more powerful Energy Blast. Valefor is the only aeon to have two Overdrives, and is revived after 8 battles should she die.
Energy Blast is obtained by speaking to a girl and her dog in Besaid Village. To break the damage limit, Yuna must have obtained her Nirvana, and power it up with the Moon Crest. Later in the game Valefor is so fast that if Sonic Wings is used repeatedly against a single opponent, they never have an opportunity to attack. Because Valefor is a flying aeon, some enemies cannot hit her at all due to their attacks only hitting ground targets (an example being Omega Ruins' Demonolith).
Ifrit, the Fire aeon, is located at the Kilika Temple. His fayth is a male Crusader. Ifrit specializes in the Fire element, but his special attack, Meteor Strike, is non-elemental and bypasses the Protect status. His Overdrive, Hellfire, is a powerful Fire assault in which Ifrit hurls fireballs at the enemy, and finishes by throwing a chunk of earth at them. Ifrit is revived after 12 battles.
Ifrit has high defense, rivaling Bahamut's; however, his attack and HP are lower. As with all the elemental aeons, Ifrit can be healed by using spells of his own element on himself, meaning Fire spells are an easy way to restore his HP. To break the damage limit, Wakka must upgrade his World Champion using the Jupiter Crest.
Located at the Djose Temple, Ixion is the Lightning aeon. Ixion's fayth is a man in a sailor's outfit, but he manifests as a unicorn with a gargantuan horn. He possesses high Magic and Magic Defense and uses the attack Aerospark to deal damage and dispel all positive status enhancements (except Auto-Life) from the target. The ultimate Lightning attack, Thor's Hammer, encases the enemy in a field of electricity and sends it crashing into every other enemy on the field.
Ixion can heal by using Lightning-based elemental attacks on himself, and is revived after 20 battles. To break the damage limit, the Saturn Crest must be used on Kimahri's Spirit Lance.
Shiva is the Ice-elemental aeon of the Macalania Temple. Her fayth is a Macalanian priestess, and she possesses high evasion and speed. Shiva's Heavenly Strike deals non-elemental damage and inflicts the Threaten status (despite the in-game description stating it inflicts delay), and her signature attack, Diamond Dust, freezes the battlefield and all of Shiva's opposition. With a snap of her fingers, the ice shatters, and deals Ice damage to all enemies. Shiva revives after 20 battles.
Shiva rivals Bahamut in power due to her high speed and evasion; combined with Haste she becomes a force to be reckoned with. Unlike Bahamut, Shiva can heal herself with Ice-elemental attacks. Shiva can break the damage limit once Lulu's Onion Knight has been upgraded with the Venus Crest.
Bahamut is the final mandatory summon. He is a large, black dragon with enormous red wings. He can stand or move in either a bipedal or quadrupedal fashion. In his fayth form of a young boy, he acts as Tidus's guide in Spira. He is the one who reveals the truth about Tidus and his hometown's origins and that Tidus was brought to Spira to defeat Sin for good. Only Tidus and Yuna can see him. In Final Fantasy X, Bahamut's fayth acts as the collective representative of all fayth, and communicates with Tidus and Yuna.
Bahamut is considered the strongest storyline summon. He is slow but his Impulse attack and Mega Flare Overdrive are powerful, both dealing large non-elemental damage to all enemies. Bahamut can break the damage limit natively, and revives after 24 battles.
Anima can be sought out after the party has the airship, has found the Baaj Temple, and after having collected the Destruction Sphere treasures in all six Cloisters of Trials. Anima awaits in Baaj Temple's Chamber of the Fayth. Her fayth is Seymour's mother, whom Yunalesca turned into a fayth so Seymour could become a powerful summoner. He has since been consumed by lust for power, searches for a way to control the ultimate power: Sin.
Anima offers her powers to Yuna in the hopes she can stop Seymour. The help bar when summoning her inside Sin says "Thus I atone". Similarly, if she is summoned during the battle against Seymour Omnis, he will remark on her opposing him, saying "You would oppose me as well? So be it".
In battle, Anima is extremely strong. Her special attack, Pain, deals high damage and can inflict Instant Death to an enemy. Her Overdrive, Oblivion, deals colossal damage to all foes. In the PAL, International, and HD Remaster versions, Oblivion deals 16 hits of damage instead of just one, as it does in the NTSC and Japanese versions. Anima revives after 24 battles.
Originally located at a Temple of Yevon, Yojimbo's fayth—a Crusader and his dog—is now within the Cavern of the Stolen Fayth. The player must defeat Lady Ginnem's Yojimbo, and then offer Yojimbo's fayth a large sum of gil, usually in excess of 200,000. If the player then pays Yojimbo triple what he is asking, he will give two Teleport Spheres as a token of his appreciation. This will still work after having "haggled" with him. Lulu tells Tidus that Yojimbo was stolen from a temple because people (possibly Al Bhed) did not want summoners to sacrifice themselves while calling the Final Aeon.
Yojimbo is a unique aeon, as his attacks are based on a complex calculation of loyalty, pay, his Overdrive bar, and random chance, and are executed by giving him gil. He must be paid at least 1 gil to act. The larger the sum, the better the attack, and frequent use and paying large sums of money make his stronger attacks more probable.
When given gil, Yojimbo will use one of four moves: Daigoro (where his dog Daigoro attacks in his stead), Kozuka, Wakizashi, or Zanmato. Daigoro and Kozuka injure a single foe, Wakizashi one or all, and Zanmato instantly defeats all opponents, including bosses and superbosses. While Yojimbo has no Overdrive, the chance of executing better attacks increases with a full Overdrive bar. Yojimbo revives after 24 battles.
Yojimbo requires Auron's Masamune to be upgraded with the Mars Crest to break the damage limit.
The Magus Sisters
The Magus Sisters can be obtained once the player has received all other aeons, the Blossom Crown and the Flower Sceptre. The Magus Sisters' fayth, three young women, can then be approached in the Remiem Temple.
Cindy the ladybug, Sandy the praying mantis, and Mindy the bee, each has her own field of expertise. Cindy excels at White Magic, Mindy at Black Magic and defense, and Sandy at physical attacks and support White Magic, although Cindy is the one who knows Ultima, and Mindy has one of the most powerful attacks in the game, Passado, her special attack that deals 15 hits of physical damage to a single target. Cindy and Sandy's special attacks, Camisade and Razzia, deal physical damage to one target. The Magus Sisters revive after 30 battles.
Commanding the sisters is different from the other aeons. The player can only "suggest" what they should do, which could result in them doing anything, including having a rest, or casting Cure on another sister in dire need of Curaga. The sisters are still very powerful, as they can deal high damage from the beginning.
To launch their Overdrive, each sister's bar must be full, and the command "Combine powers!" selected. Delta Attack deals high damage to all foes, either in one lump sum, as it does in the NTSC and Japanese versions, or six successive hits like it does in the PAL, International, and HD Remaster versions.
The Final Aeon
The Final Aeon is created from someone who shares a deep bond with the summoner: a friend, family member, or lover. Lady Yunalesca was the first to call the Final Aeon, her husband: Lord Zaon. Yu Yevon, the mindless, unsent spirit of the ruler of Zanarkand 1000 years ago, resides inside of Sin and uses it as his armor. The Final Aeon can pierce Yu Yevon's armor, and destroy Sin, but once Sin is defeated, Yu Yevon takes control of the Final Aeon severing the bond between it and the summoner, killing the latter. Yu Yevon then uses the Final Aeon to rebuild his armor, making the Final Aeon the new Sin. The period of peace before the rebuilt Sin returns is known as the Calm.
When the Final Aeon destroys Sin, Yu Yevon takes the pyreflies that the Final Aeon is composed of to form the next Sin, and the fayth's soul becomes trapped within Sin as the pyreflies that contain the fayth's soul physically become Sin's core. Eventually, the fayth will lose its consciousness and be totally absorbed into Sin. When Sin is defeated its pyreflies are dispersed into the surrounding atmosphere, including the pyreflies of the previous Final Aeon.
When Seymour Guado was young his mother brought him to Zanarkand and had Yunalesca turn her into a fayth for Seymour to obtain the Final Aeon, but Seymour never used the aeon he'd obtained to battle Sin.
Obtaining the Final Aeon is initially Yuna's goal, but after she learns of the futility of defeating Sin with the Final Summoning, she rejects it and decides they must find another way. They pacify Sin via the "Hymn of the Fayth" and fly into it with their airship and traverse Sin's innards till they reach the core. In the final battle before challenging Yu Yevon, the party fights Braska's Final Aeon, Jecht, the last fayth Yu Yevon used to create Sin.
When machina was invented it was revolutionary and did away with the inequalities and spread throughout Spira. Machina developed quickly, and things once thought impossible became an aspect of everyday life. The endless supply of electricity made "cities that never slept" a reality. Machina was supposed to be an alternative for those who couldn't use magic, but when it surpassed it new problems arose. Some nations possessed outstanding machina technology, while others didn't, and a new age of inequality began.
As told in Final Fantasy X-2.5 ~Eien no Daishou~ there was once a mechanic called Alb who created a race called Bedohls, humans who could not use magic but excelled at wielding machina, and used them to combat a mage from Zanarkand. The term "Al Bhed" is a corruption of "Alb" and "Bedohls." Their weapons were so powerful they were kept under surveillance at all times. It is speculated their power was the catalyst for the Machina War.
When the Machina War broke out between Bevelle and Zanarkand, Bevelle using mainly machina for weapons while Zanarkand depended upon its summoners, Zanarkand was left devastated. Bevelle built the machina weapon of unspeakable power, Vegnagun, but deemed it too dangerous for ever to be used and it was sealed in Bevelle Underground. Near the end of the war Bevelle's superior machina gave them the upper hand and Zanarkand was about to lose. Zanarkand's survivors were made into fayth by the summoner Yu Yevon for a mass summoning.
To protect himself amid the summoning Yu Yevon gathered millions of stray pyreflies around himself, forming an armor which would later became known as Sin. Not to become distracted from his summoning, Yevon "programmed" a series of guiding instincts into Sin: among them, to attack any larger human settlement, to attack any machina, and to respond to aggression with overwhelming force. Yu Yevon lost control of Sin and became trapped inside its instinctive behavior, from then on living only to summon. No longer under control Sin attacked the nearest human settlement destroying the real Zanarkand, and proceeded to decimate the incoming Bevellian army.
From that point onwards Sin destroyed machina cities, becoming a terror to all Spirans and uniting Spira under a common fear. The citizens of Bevelle at that time thought that what Yevon had summoned from the Zanarkand fayth was Sin that was going around destroying everything as a sign of Yevon's anger.
Yu Yevon's surviving daughter Yunalesca made her husband Zaon into a fayth for the Final Summoning and defeated Sin. The moment Sin's shell was cracked Yu Yevon possessed Zaon's aeon, and began building a new Sin around it.
With Sin's "defeat," a short period of peace settled on Spira, known as the First Calm, and the survivors began reconstructing Spira, focusing on Bevelle. Yu Yevon regenerated Sin using Zaon's aeon as a core, and the new Sin destroyed the remaining machina civilizations and thus machina use began to fall out of favor. The Yevon Temple was established in Bevelle and the teachings of paying homage to Yevon and Yunalesca, and preaching of machina prohibition, were adopted by the world at large. The new religion established Sin as a punishment for people's sins spreading the story that the Calm will arrive with the Final Summoning. After the Temple of Yevon was established the Al Bhed were blamed for the emergence of Sin and executed in numbers, thereby casting them out of society.
Machina is forbidden by Yevon due to its potentially destructive nature, save for a few exceptions (such as the blitzball sphere pool). Al Bhed continue to be considered heretics for their rebellion against Yevon's doctrine, as well as their salvage and use of ancient machina. Bevelle shows its duplicitous nature in its own secret machina use, knowing of Sin's true origin and that it cannot be banished by the Final Summoning. The Bevelle Temple is full of machina, and the armies of Bevelle wield machina weapons.
By Final Fantasy X-2, machina has come into wider use due to the fall of Yevon as the main political force, although many are uncomfortable with its use. As a result, newly built machina are branded "machines." Al Bhed are no longer viewed as heretics, and with the use of machines spreading through Spira hovers replace chocobos at Mi'ihen Highroad.