Final Fantasy XV Whole Story

Alright. As is well known, the story of the game opens with Noctis and his companions Gladiolus, Ignis and Prompto heading for Altissia. They learn that Niflheim has broken a peace accord, killed Noctis' father Regis, and stolen the Crystal. Said Crystal was a gift from the world's deities, granting prosperity to mankind in the wake of an ancient catastrophe (more on that later). The world is already in a bit of a state, as the nights are gradually growing longer through a supernatural malady called the Starcourge, causing monsters called Daemons (Shigai or something like in Japanese) to run rampant and attack anyone not within the confines of a town or blessed areas called Havens. Note: It is very much advised that you watch both Kingsglaive and Brotherhood, as without it some parts of the story will be utterly incomprehensible.

Anyway, Noctis has to go on a quest to recover Royal Arms from the tombs of previous Lucian kings, prompted by Cor Leonis. He is also prodded along the path by Ardyn, who despite being the Imperial Chancellor is more than willing to aid Noctis in his quest despite its repercussions on Niflheim. Ardyn also guides Noctis to the doorstep of the Archean Titan, one of the Six Astrals, divine beings that protect the world of Eos. Noctis undergoes Titan's trial and is granted his powers. He then learns that Lunafreya had previously visited, waking Titan and persuading him to put Noctis to the test. Lunafreya is key to this: she awakens each Astral and forms a Covenant with them, which acts as an intermediary through which Noctis can access their powers. However, doing this takes a dire tole on Luna's physical health, as she grows weaker during her journey. She continues on the path because she is the Oracle, the hereditary companion to the prophesies True King, foretold to guide him to purge Eos of the Starscourge. Noctis is next guided to the Fulgarian Ramuh with help from "Gentiana", Lunafreya's spirit companion. They also meet others, including the mercenary Aranea Highwind, who is first ordered to accompany them and then gets into a fight when they attack a base. They also meet Ravus, who is by no means impressed by Noctis.

Things come to a head when Noctis and co. come to Altissia, where Lunafreya wakes the Hydrean Leviathan, who is more than annoyed at being awakened by inferior, forgetful humans. She nevertheless accepts Covenant, but the Empire attacks and disrupts the entire ritual. Noctis must face Leviathan alone as the others are aiding in evacuation efforts around the city. Noctis is stunned by Leviathan's attack, and Ardyn appears and stabs Lunafreya, mortally wounding her. She uses the last of her strength to temporarily awaken Noctis' potential as the True King. Noctis defeats Leviathan with the help of Titan, then falls into a coma. In that coma, he meets Lunafreya's spirit, who gives him the Ring of the Lucii that she received in Kingsglaive. Upon waking with the ring, Noctis learns that his companions didn't escape unscathed: though Gladiolus is just scarred, an attack on Ignis has rendered him all but blind. This creates a schism in the group until Ignis snaps at them and forces a reconciliation, particularly between Gladiolus and Noctis.

Taking a train towards Galea, Niflheim's capital, Noctis is tricked by Ardyn into throwing Prompto from the train, which is then attacked by Daemons and saved by Leviathan. Arriving in Tenebrae, they meet Aranea, who has abandoned her former employers. She is helping civilians defend against Daemons, and assigns former Imperial officers Biggs and Wedge to take the train with Noctis and crew on to Galea: they learn from them that the entire capital has been overrun by Daemons, which were forged by taking some kind of dark energy and fusing it with both objects and living things like beasts and people. Noctis also learns more about Lunafreya's actions from others in Altissia, including the fact that Ravus is actually using his position to support her and knows Noctis' role following the Ring's rejection of him. The group travel on, passing through a place where the body of the Glacian Shiva rests. Shiva seemingly attacks them, and Ardyn appears once again to taunt Noctis. Gentiana appears, revealing herself to be Shiva's new form, and incapacitates Ardyn before giving Noctis Lunafreya's trident. Ardyn survives Shiva's assault, revealing himself to be immortal. He then says both Prompto and the Crystal are in Galea, and that only the Crystal's light can purge the Daemon and Starscourge. (Note: This, and the following section in Galea, is more linear than XIII. No, seriously...)

In Galea, Noctis, Gladiolus and Ignis are forced to take the Regalia for the last stretch, which pretty much ruins the car. Noctis' powers are also suppressed by Ardyn, and he is separated from his companions and forced go on alone. Backed into a corner, he finally dons the Ring of the Lucii, and goes through the main Niflheim fortress while being taunted over the intercom by Ardyn. He eventually finds his father's sword, which Ravus had been meaning to give to him - he also finds Ravus with it, dead along with numerous soldiers from a Daemon attack. He reunites with Ignis and Gladiolus, and frees Prompto, who it turns out was born from the same kinds of procedures as the Daemons: he is a 'product' of the empire. They also encounter both Iedolas and Ardyn, now transformed into half-demons by Ardyn. Attacked by Daemons on all sides, Noctis is forced to go on alone. He finds the Crystal and asks it to purge the Daemons, but instead it begins to drag him into it. Ardyn then appears again, and reveals his secret: he, whose real name is Ardyn Lucis Caelum, is the first Lucian king who was called by the Astrals to purge the world of the Daemon malady, but he absorbed them into himself to spare countless lives. But another who was eventually to become the Crystal's chosen, demonized Ardyn and caused him to be cast out (he heavily implies that Noctis' ancestor was the true "Izunia"). The darkness within him, and being hated by the people, drove him insane: he has been pushing to destroy the Caelum line, having Noctis acquire the power so he could face a worthy foe and destroy both the family line and the crystal.

Inside the Crystal, in an astral realm, Noctis is met by the Draconean Bahamut. The realm is where Noctis will gain his power as the True King, his friends will wait and continue fighting until that time, and his fate is to destroy "the immortal Accursed" Ardyn then absorb the Crystal's remaining light into the Ring of the Lucii and "ascend", destroying the Daemons and Starscourge at the cost of his own life. Having gone through this trial, Noctis awakens in one of the tombs near Lucis, having aged with the passing of ten years. Reunited, Noctis, Gladiolus, Ignis and Prompto travel to Insomnia, where Ardyn waits for them. (During this segment, the vocal version of "Somnus" plays, it gets you) Upon reaching the royal palace, Ardyn summons Ifrit the Infernan, an Astral with no love for mankind. Noctis defeats and destroys Ifrit with the help of first Bahamut and then Shiva.

The group confront Ardyn, who immobilizes everyone but Noctis as the coming battle is only for "kings". Noctis and Ardyn have a final titanic duel outside the palace, which ends with Ardyn slain while the Lucii look on from around. He heads inside, while his friends stay outside to keep the Daemons at bay. Noctis ascends to the throne, summons the Lucii and absorbs their power and the Crystal's light into himself and the ring, including Regis. This act kills him, and sends out a burst of light that erases the Daemons from Eos. Now in the netherworld, Noctis and Lunafreya confront and destroy Ardyn's spirit with the Lucii. The Ring fades away. We then see the group's emotional final meeting together prior to the final battle. In the real world, the dawn rises on Eos. (Note: There are no bodies in the courtyard of Insomnia's palace, and given the context of Noctis' final confrontation with Ardyn and how they survived ten years of Daemons, I think Gladiolus, Ignis and Prompto survived to help the world rebuild).

In the very final scene, in a strange dream-like vision (accompanied by the Final Fantasy theme), Luanfreya and Noctis are upon the throne as king and queen. The air is filled with petals and crystal shards. They share a kiss, and go to sleep together. The pair then transform into a new version of the FFXV logo; Luna is the sleeping winged goddess, while Noctis sleeps by her side.