major ffxv spoilers ahead!

the world of eos was comprised of three continents: lucis, accordo, and niflheim. the northeastern land of lucis possesses a powerful crystal, which was gifted by the gods in antiquity to the reigning lucis caelum dynasty. accordo, located in the south, is made up of islands and has been annexed by the niflheim empire, which lies to the west and benefits from its advanced magiteknology. the province of tenebrae is under niflheim's control, but maintains some autonomy due to the presence of the oracle, a priestess who has the power to fight the starscourge, a plague that lengthens nights and turns people and animals into vicious demons. watching over eos are the six astrals, divine beings that can appear in the mortal realm, usually as colossal and powerful beings.

for hundreds of years lucis and niflheim have been at war. while many lands have been lost to the niflheim empire, the lucian capital of insomnia remains untouched due to the wall, a transparent magic barrier maintained by the king and the crystal's magic. peace talks have begun in hopes of bringing an end to the conflict, one of the conditions being a marriage of prince noctis and lady lunafreya, the oracle of the gods.

at age twenty, noctis sets forth from his homeland insomnia to formalize the union of states through his marriage to lady lunafreya of the imperial province of tenebrae. accompanying noctis are his closest and most trusted friends—ignis, his royal advisor; gladiolus, his bodyguard; and prompto, his best and only friend from high school. noctis tried to meet with his father, king regis the day before he left, but the king was too busy with the treaty-signing preparations. lucis was to relinquish all territories outside insomnia to the empire in exchange for peace. regis knew it to be a trap, but didn't tell noctis of the true reason he is being sent away from the city with his friends.

soon after, noctis learns that niflheim has attacked the crown city, the wall has fallen and the empire has stolen the sacred crystal gifted to the lucis caelum line of kings. noctis's father, the previous king, was reported dead, thus resulting in noctis becoming the new king of a fallen city. noctis attempts to turn back to insomnia, but an imperial blockade prevents him from reaching his home.

throughout his journey to meet with lunafreya, noctis is presented false aid by an imperial chancellor by the name of ardyn izunia. unbeknownst to noctis, ardyn is the immortal accursed prophesied to bring darkness to the world by the astrals. his immortality stems from the selfsame scourge that wrought the demons upon eos and lengthens the night. his mind is twisted by spite and bent on revenge for a past betrayal of the lucis caelum line, his purpose is to bring darkness to the world. while ardyn's fate is to bring darkness upon eos, noctis's ordained destiny is to be the king of light - the chosen king able to put a stop to the accursed's madness.

after the death of oracle lunafreya at ardyn's hand, noctis is met with ice god shiva, who informs him of ardyn's curse and noctis's future to become the chosen king. noctis, filled with rage due to his fiancee's death, follows ardyn to the city of insomnia's ruins where the two fight to the death in the king's citadel, for power of the six. noctis grows careless, fueled by his anger and the knowledge that it is his ordained destiny to reign victorious, and ardyn is able to overpower the king of light after a strenuous fight.

before the accursed is able to defeat noctis with his death, god of war bahamut stops time in order to force the crystal - previously stolen by the niflheim army - to absorb noctis into safety. inside the crystal, noctis meets with the draconian astral who has grown livid with the king of light's failure. bahamut bestows a new fate upon noctis - to prove himself worthy by preserving the safety of present day earth. if noctis fails, he will be punished eternally by bahamut himself. if he succeeds, the god of war has promised him a second chance in saving eos.

as promised by bahamut, noctis awakens on earth in 2019 with no knowledge of his surroundings, nor with any idea of his calling excluding that he must preserve the world. from what, he has not been informed. he is quick to notice that demons, attracted by his presence, have followed him from eos to earth, but thus far, it's been made apparent that he's the only one equipped with the ability to see them manifested.

motivated by the desire to return home to his people and his friends in eos, noctis grows desperate to find out exactly what it is that bahamut has placed him on the foreign world of earth to do, but he quickly becomes frustrated when he realizes that his new journey has only just begun.

unbeknownst to noctis and contrary to bahamut's promise, eos has fallen to darkness in the wake of the king of light's absence and the accursed's reign as king of demons.

a r m i g e r ⠀⠀⠀⠀⠀⠀⠀⠀the royal arms, also known as the glaive of kings, are special weapons in that only noctis lucis caelum and others of his bloodline can brandish - they are the weapons of the previous monarchs of lucis. there have been 113 rulers, but there are only thirteen known royal arms that have survived until eos' present day. the power of kings is to wield all of their collected royal arms simultaneously, an ability known as armiger.

when a royal arm recognizes its rightful wielder, it will become transparent and crystalline before entering the king's body, signifying the bonding of the souls of the past lucian rulers and noctis himself. from then on noctis can forge the weapon from thin air at his will. he has the ability call upon all of the royal arms he has thus collected and wield them simultaneously, gaining the power to use the armiger.