FF15

-The game was originally supposed to be divided into a trilogy of three games, later changed into three chapters within one game
-There were four crystals owned by four nations: Lucis (based off of Tokyo, Japan), Accordo (based off of Venice, Italy), Tenebrae divided into southern Tenebrae (German fantasy theme) and northern Tenebrae (Oriental/Japanese theme), and Solheim (Arabian theme). A fifth nation, Niflheim, conquered Solheim a long time ago, and eventually Tenebrae and Accordo too, quickly using up all their crystals' energy. This led to Lucis's crystal being the last active crystal in Eos, setting up the main conflict in the game. Niflheim itself was originally made up of a bunch of "non-crystal" nations, which were united a long time ago under one nation by the Aldercapt family.
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-The first chapter started with the invasion of Insomnia by Niflheim (instead of the Kingsglaive movie)
-The invasion was orchestrated by Iedolas, the Emperor of Niflheim, and Clarus Amicitia, a cousin of King Regis and father of Gladiolus and Iris Amicitia, although Clarus's role is hidden during the first chapter
-Glauca was introduced as a Lucis general related to Cor Leonis (either brother or twin brother) and Glauca was loyal to Clarus over Regis, working with Niflheim to help set up the invasion. Known as the “strongest” general in the Lucis army. Glauca does not kill Regis, Clarus himself kills Regis at the end of the first chapter.
-Noctis met and fought Aranea for the first time during the invasion of Niflheim. She is a mercenary hired by Niflheim, and stops working for them when they stop paying her in the later games, pretty much exactly like in the final version.
-Ravus was the final boss of the first chapter. He and Stella Nox Fleuret were both from Tenebrae, and Ravus knew about the true intention of Niflheim to invade Lucis, while Stella did not. After several encounters throughout the first chapter with his hood on, he reveals himself as Stella’s brother before the final boss fight. Although nominally a general of Niflheim, he was secretly working for Ardyn, and was specifically there to protect and capture Noctis under Ardyn's orders, and make sure Iedolas doesn’t kill Noctis (during the first chapter, Ardyn's identity as Ravus's master is hidden). At the end of the boss fight, Ravus manages to escape from Noctis.
-Ardyn was portrayed as a silly and disinterested bureaucrat for most of the first chapter, kind of like how he is portrayed in the final version, in contrast to the other serious and calculating generals of Niflheim, with very few hints dropped in the first chapter that Ardyn is somehow the one pulling the strings behind the scenes
-The first chapter ended with Niflheim's invasion of Lucis being a success and a new puppet government for Lucis being set up under Clarus, who agrees to share his crystal's energy with the rest of the world. Noctis and his gang escape the city and look for a safe haven to plot "revenge". Other characters also escape from the city, such as Cor, Iris, etc.
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-In the second chapter, Noctis and his gang traveled across the continent and meet up with Cor Leonis, who reveals to Noctis that Clarus worked with Niflheim to kill his father and take the throne, sending Noctis into a rage. After calming down, Noctis and Cor decide to keep Clarus's role from Gladiolus a secret for now. (Leaker’s note: Gladiolus, Iris, and the others assume Clarus is being held “hostage” by Niflheim, not that Clarus was actively helping them)
-Cor's plan was to organize a resistance among the other nations against Niflheim by announcing that the true king of Lucis is still alive, and tells Noctis to meet him in Accordo
-During Noctis and Cor’s discussions with the leader of Accordo, an Accordan bureaucrat who was opposed to the current Accordan leader and valued Accordo’s relationship with Niflheim over Lucis, told Niflheim about Noctis's presence in the city, causing Niflheim to send an army to reoccupy Accordo which previously enjoyed a privileged status under Niflheim (Leviathan is awakened during this part to "defend" the city from Niflheim, and Noctis is forced to kill Leviathan because it was losing control)
-As the city was no longer safe for Noctis, Cor and the gang decided to head to Tenebrae, which in the absence of Ravus and Stella Nox Fleuret is currently under the watch of the “Oracle”. Noctis also hopes to learn the whereabouts of Stella, whom he met in the first chapter during the infamous "party scene", and has been unable to stop thinking about since, despite Stella’s request to Noctis that he forget about her as they are on opposite sides of the war. Noctis constantly sees images of Stella, including whenever he sleeps, throughout the second chapter.
-Upon arriving in Tenebrae, they met with the Oracle (Gentiana), who hails from the lands "north" of Tenebrae (not actually just north, but on a completely different continent). She wears oriental-style clothes, unlike the rest of Tenebrae who wear mostly pure white, European-style clothes (contrast to “Lucis style” pure black, modern clothes). She has two assistants also from northern Tenebrae, and they are all able to shapeshift between human and avatar (animal) forms.
-(Lore flashback) Gentiana tells Noctis about the origins of Eos, which was created by the goddess Etro, who appointed a guardian to watch over the people of this new world. That “guardian” noticed that the humans of Eos were always fighting eachother over the power of the four crystals, so he came up with the idea of creating a common enemy for the humans to unite against to end the fighting amongst humans. That enemy became known as “demons”. Etro did not approve of the guardian’s plan and stripped him of his powers, forever trapping him in the body of a mortal. Gentiana fears that the current demons used by the Niflheim army could be the same as the demons created by the guardian, and speculates that the ruling family of Niflheim is related to the guardian. Gentiana tells Noctis to travel to Niflheim, where Stella will be waiting for him, and to find out the truth behind the demons and destroy them, and that Tenebrae would help Noctis take back the throne.
-The continent of Niflheim was based off of industrial age Great Britain, and there are large mines and smelting factories all over the continent. The capital itself is more modern.
-Noctis and his gang arrived at where they were supposed to meet up with Stella, but instead they get ambushed by Niflheim soldiers, led by Ravus, who is badly scarred from their last encounter
-In prison, Ravus explained to Noctis that he is not Noctis’s enemy, and that he is also working to free Tenebrae from Niflheim. He frees Noctis and his friends, and tells him the location of where research is conducted on demons, led by Verstael.
-Once in the laboratory, Prompto started losing control of his body, and leaves the party. There is a lot of human experimentation in the laboratory, especially on humans from Solheim and outer Niflheim. In the original plot, demons were the “final” form of humans. Humans from Solheim (mostly long dead corpses) and other nations were used by Niflheim to create demons for use in the military. The party finds Verstael, who is in control of Prompto, and who reveals that Prompto is his son that he conducted experiments on that failed. Verstael’s goal is to unlock the “final” potential of humans, and he turns himself into a half-human, half-demon (boss fight). The party defeats him and rescues Prompto.
-The party then decided to find the Emperor and end Niflheim’s research on demons. Upon falling into a trap laid by the Emperor, the Emperor reveals his goal is to use the energy of the final crystal to conduct research on technology that can replace the crystals, allowing the Aldercapt family to rule over the world forever with a monopoly on the technology. The Emperor attacks the party (boss fight), but Ardyn intervenes, killing the Emperor, saying that his research would be a waste of time. Ardyn then reveals that he was the master of Ravus in the first chapter, the “guardian” that Gentiana spoke of, and the one who provided Verstael with the research on demons (leaker says this is supposed to be very surprising, Ardyn receives pretty much no screen time up until this point in the game).
-(Lore flashback) Ardyn tells Noctis he has been helping Niflheim for centuries since Niflheim’s founding to help conquer the other nations. He created the “demons” by simply letting out the true emotions hidden within all humans, but Etro grew jealous of his power, and sent a son created out of love to rule over the world instead; this eventually became the Nox Fleuret family. But before Etro returned to her realm, she got seduced by lust by another mortal, creating another family that had the power of Etro; this eventually became the Lucis Caelum family. Etro was so ashamed by her actions that she left the world of Eos to never return. Ardyn’s goal is to use up all the energy of the final remaining crystal, creating a conflict between the descendants of Nox Fleuret and Lucis Caelum, and between humans and demons, resulting in Etro opening up the gate to this world as Etro unconsciously desired to reunite with her children (Nox Fleuret and Lucis Caelum), and allowing Ardyn to finally return to the realm of the gods. For this to happen, he tells Noctis he needs him to let out his true emotions, and he sends a resurrected, uglier version of Verstael’s demon after the party (final boss fight). This causes a large part of the capital building to collapse, forcing Noctis and the party to flee. As they are trying to escape the collapsing building, Stella appears and rescues them. At first, Noctis believes Stella’s appearance is just another hallucination (this is the first time Stella appearing in person since the first chapter). The second chapter ends with Noctis, his gang, and Stella leaving Niflheim, with Iedolas being announced dead and (a resurrected?) Verstael being announced as the new Emperor of Niflheim.
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-The final chapter began with Noctis, his gang, and Stella returning to Tenebrae. Noctis is still in shock from what Ardyn told him in the previous chapter. Stella explains that she learned the truth about their families from Ravus, who learned it from Ardyn. Ravus believed that Etro returning to this world was the only way to return light to the three expired crystals, and that the only way to do this was to defeat Noctis and the Lucis Caelum family and relieve Etro of her shame. Thus Ravus worked with Ardyn to achieve this goal, until he learned that Ardyn’s only goal was to return to the realm of the gods, and that he was willing to destroy Eos to achieve this. Meanwhile, Stella, with the support of Gentiana, disagrees with her brother that there is only one way to return Etro to this world, and believes that as descendants of Etro, they should have the ability to communicate directly with her through the crystal. Noctis, still angry at his father who he assumes knew the truth about his family yet did not tell Noctis, agrees with Stella for now and they decide to return to Lucis where the final crystal is located.
-On the way to Lucis, in order to communicate directly with Etro, Noctis and Stella acquired the seven Astrals: Ifrit (near Solheim, now near Niflheim), Bahamut (near Niflheim), Fenrir (near Tenebrae), Shiva (Tenebrae, in the acquisition of Gentiana), Leviathan (Accordo), Titan, and Ramuh (near Lucis)
-In Lucis, Noctis and his party infiltrated the palace, where they encounter Glauca. This is an unbeatable boss fight, and you have to run away.
-Gladiolus found out that his father was the one responsible for killing King Regis, and leaves the party due to doubts about whether he should be loyal to his father or Noctis.
-Noctis confronted Clarus, who tells him that his father (King Regis) knew the truth about the Lucis Caelum family, and that Regis was prepared to end his bloodline in order to end the curse of Etro on Eos, but Clarus was not prepared to let Regis just end the family line like that, and worked with Niflheim to take the throne from him. Clarus then attacks Noctis (boss fight), but Gladiolus appears to defend Noctis from his father, resulting in Gladiolus’s death, which causes Noctis to let out his true emotion and kill Clarus (fulfilling one of Ardyn’s conditions).
-Ravus arrived just as Noctis kills Clarus, and tells Stella that Noctis, who now resembles a demon, must be killed. Control switches to Ravus, and you attack Noctis (boss fight). After the first stage, the boss fight becomes unbeatable in the second stage, and Ravus is defeated by Noctis.
-Ravus told Stella with his final words that as the last Nox Fleuret, that the fate of Eos is now in her hands. Noctis absorbs all the remaining energy from the final crystal, which causes all four crystals in the world to shatter, turning people near the four crystals and all over the world into demons. The area around the final crystal turns into a gateway to the Kingdom of the Dead, and draws everybody in.
-In the Kingdom of the Dead, Stella and the party found Etro (each of the party members, including Gladiolus, goes through their own individual trial in the Kingdom of the Dead). Etro is sleeping (same pose as the logo) and Stella pleads with her to wake up, but Ardyn arrives and says that it is useless, as Etro no longer cares about Eos or its people. Ardyn then attempts to kill Etro to take revenge, but is instead absorbed into her. This causes Etro to wake up, who is horrified by what has happened to Eos, but is happy to finally be reunited with the Nox Fleuret (Stella). Etro asks Stella to stay with her and leave Eos behind, but Stella refuses, causing the Ardyn part of the Ardyn-Etro hybrid to grow in prominence, and absorb Stella too.
-Back in control of Noctis, Noctis went through his own trial in the Kingdom of the Dead, involving his father and his mother, Aulea Lucis Caelum (childhood Noct gameplay portions). After seeing how much his father and mother loved him, his hate for his family and his family’s origin subsides, and he becomes less demonic. Noctis emerges from his trial to find the Ardyn-Etro-Stella hybrid (the hybrid is giant, resembles the Barthandelus-Lindzei-Orphan hybrid at the end of FF13). Reunited with his party, he fights the hybrid, first destroying the Ardyn-Etro-Stella hybrid (by climbing the hybrid and destroying the Ardyn part on top), then an Etro-Stella hybrid (resembles an image of Etro embracing Stella), and then finally a one-on-one fight without his party members against Stella, who is free from Etro’s control but still influenced by Etro’s desire to destroy the Lucis Caelum (final boss fight). After freeing Stella, Noctis tells her that he will stay behind in the Kingdom of the Dead with Etro, freeing Eos from Etro’s shame once and for all, while Stella pleads with him not to. Noctis fuses with Etro, and then opens up a gateway, pushing Stella and the party to the other side. The final chapter ends with both Lucis and Niflheim ending their monarchies, with Lucis being headed by Ignis and working with Niflheim to finish the research to replace the now shattered crystals, Stella visiting someone's grave (Ravus?) before leaving Tenebrae in the hands of Gentiana and heading off on a journey (to find Noctis?), and Noctis sitting on the throne of Lucis sleeping.