Disc of Cauthess is a meteorite impact site in the Duscae region in Final Fantasy XV. It has glowing crystal formations in the middle. The energy from the still-active crystals is used by the EXINERIS Industries power company in Lestallum to provide the entire region with electricity, although they are said to use smaller shards that were scattered around the region, rather than the crystal in the Disc of Cauthess.
The region's topography is dominated by the meteor impact site, and the crystal still exudes heat, people describing it as "being on fire". Its heat is harnessed to power Lestallum. It glows blue and is the most prominent landmark in the region. It is known as The Meteor of the Six or the astral shard. The astral Titan is said to reside in the Disc, holding up the meteorite. The valley has numerous smaller craters around the Disc of Cauthess.
Visiting the Disc comprises Chapter 4.
Titan the Archaean is an astral god said to have caught the meteorite that fell to Eos and to still be holding up its active remains at the center of the impact site. This tale has become a legend, and the tremors that sometimes emanate from the Disc are said to be the work of Titan himself. Though millennia have passed, the meteorite still radiates heat. It is said the meteorite broke into pieces when it was caught by Titan. EXINERIS Industries in Lestallum converts heat from the meteorite fragments into electricity, and thus many have a favorable view of it. The meteorite is visible as giant spires in the Disc of Cauthess that the glow at night. The craters and ponds in the Duscae region are believed to have been made when the meteorite fell.
When Prince Noctis is heading for Lestallum after the Crown City is invaded by the Niflheim Empire, he has a chance of visiting the Disc of Cauthess on his way. If they do so, Noctis's party finds the site closed off by the imperials, although they cannot fathom the reason.
Once in Lestallum Noctis experiences visions of the Disc accompanied by searing headaches, and the Disc shakes sending tremors throughout the region. Deducting it to be call from Titan as per legends that the astrals forge covenants with the kings of Lucis, Noctis wants to head there. Chancellor Ardyn Izunia promises to open the way to the Disc through the imperial barricades, and although Noctis is skeptical he follows Ardyn there, at first unaware he is the chancellor of the enemy empire.
Ardyn opens the imperial gates to let Noctis's party into the Disc of Cauthess, but will not accompany them. Noctis comes face-to-face with the Archaean Titan that rises from underneath the glowing meteorite. Noctis cannot understand what Titan wants until he has a vision of Lady Luna communing with the astral, realizing that she wants to rouse the astrals to help Noctis's cause. Titan's awakening sends tremors in the region and Noctis and his bodyguard Gladiolus are separated from the rest of the party as they fall into the pit under the meteorite that is burning hot.
Noctis and Gladiolus make their way to Titan through the burning rock. Gladiolus protects Noctis and grows frustrated, asking the latter to reaffirm his conviction to be the king of Lucis. Niflheim arrives to the site and attacks Titan, and Noctis and his party are caught in the crossfire.
Titan engages Noctis who must parry the giant's attacks until his friends arrive to blast Titan's arm off with blizzard spells. Forging a covenant with Noctis, Titan disappears from the Disc. Noctis's party is given safe passage out of the crumbling crater by an imperial airship on Ardyn Izunia's orders. Though unsure why Ardyn, an enemy official, is helping him, Noctis takes the offer, but during the chaos the party loses their car, the Regalia.
News spread that the tremors at the Disc of Cauthess have died down, but that Titan has disappeared. Many worry for what the awakening of the astrals means for the world.