Tiamat: In a time before time, my father did come to this star, bearing seven eggs.Midgardsormr: From these eggs did my children hatch. And once they were full-grown, they took wing and spread across all the lands of Hydaelyn.On the first brood, Final Fantasy XIV: Heavensward
As primordial dragons, the great wyrms are among the oldest living beings on Hydaelyn, and among the most powerful. Their key source of power lies in their eyes. A single eye is a wellspring of aether that can rival other sources, such as the Tupsimati.
The dragons are an alien race originated from a planet known as the Dragonstar, driven to extinction by the warmongering Omicrons and their creation Omega. Out of the many that fled with eggs in claw, Midgardsormr ended up on the Source following the world's sundering and formed a pact with Hydaelyn for sanctuary. The seven eggs Midgardsormr brought with him hatched into the first brood, and settled across the land before their kin would come to conflict with the mortal races.
During the Third Astral Era, the Allagan Empire attacked the dragons of Meracydia with the dragons' leader Bahamut killed in battle. Bahamut's siblings Azdaja and Vrtra answered the call of Tiamat to assist in the conflict. During the chaos, Azdaja sacrificed herself to seal a voidgate the Allagans were using to fuel their forces with voidsent. The Ascians tricked Bahamut's brood-sister and mate, Tiamat, into reviving him as a primal—a decision she would regret as the Ascians also taught the Allagan Emperor Xande the means of trapping primals. While the imitation of Bahamut was sealed within Dalamud with many of the Meracydian dragons to maintain the primal, Tiamat was imprisoned in Azys Lla. She remained in self-imposed imprisonment there long after the Allagan Empire fell, and intended to stay there as penance for her sins until the end of Eorzea.
In the northern realm of Dravania, the "Skylords" under Hraesvelgr, Ratatoskr, and Nidhogg entered a truce with the Elezen "Landlords" who came to their lands during the Sixth Astral Era. Two hundred years later, the Elezen king Thordan I and his Twelve Knights broke the peace by murdering Ratatoskr for her eyes and blinding Nidhogg when he sought revenge. After Nidhogg convinced Hraesvelgr to give up one of his eyes, he waged a millennia-long bloody conflict called the Dragonsong War.
On the island nation of Thavnair, Vrtra was forced to play an active role in the nation's development by placing himself as the shadow ruler of Radz-at-Han with an Auri bloodline serving as figurehead rulers. He placed his right eye in a homunculus to observe events and maintained this ruse to prevent Thavnair from being invaded by other nations.
- Bahamut - The Dawn Wyrm, eldest of the first brood. Mate of his brood-sister Tiamat, and father of the Meracydian Horde. Bahamut fell in battle against the Allagan Empire, and parts of his aetherial essence were used to create an eikon in his image.
- Tiamat - The Dusk Wyrm, brood-sister and mate to Bahamut, with whom she founded the Meracydian Horde. Tricked by the Ascians into summoning an eikon in the image of her fallen beloved, she allowed herself to be captured and imprisoned by the Allagans in grief and penance. She was later freed and cured of her enthrallment.
- Hraesvelgr - Founded the Dravanian Horde alongside Nidhogg and Ratatoskr. Fell in love with an Elezen woman, Shiva, bringing mortals and dragons together for a time of peace and prosperity. He lost faith in mankind after his sister Ratatoskr was slaughtered, only to regain it from meeting the Scions of the Seventh Dawn.
- Nidhogg - Founded the Dravanian Horde alongside Hraesvelgr and Ratatoskr. While raised to succeed their father as the world's protector, Nidhogg held mortals in disdain and grew to hate them following Bahamut and Ratatoskr's deaths. The war he and his horde raged against Ishgard would last for a thousand years and forms the main events of Final Fantasy XIV: Heavensward.
- Ratatoskr - Founded the Dravanian Horde alongside Nidhogg and Hraesvelgr. Acted as an emissary between the Elezens and dragons during the time of peace. Was betrayed and slaughtered by King Thordan I and his Twelve Knights when they sought her power.
- Vrtra - The youngest of the first brood who resides on the island of Thavnair as the shadow ruler of Radz-at-Han, offering his aid to the Warrior of Light and the Scions in Final Fantasy XIV: Endwalker.
- Azdaja - During the Third Astral Era, Azdaja was Vrtra's caretaker. But when Emperor Xande made a pact with the Cloud of Darkness, Azdaja fought against Xande's voidsent. In order to stop them, Azdaja flew into a voidrift which closed right after she went through. Whether she is alive is unknown.