The Eyes of Nidhogg are powerful artifacts from Final Fantasy XIV that play an important role in the plot of the expansion Final Fantasy XIV: Heavensward. The literal eyes of the great wyrm Nidhogg and the source of his power, they change possession several times throughout the story as various characters seek to wield them for their own purposes.
Twelve hundred years prior to the events of Final Fantasy XIV, there was peace between Ishgard and dragonkind. The example of Hraesvelgr and Saint Shiva had proven that the two disparate societies could coexist and thrive alongside each other. Of the great wyrms, only Nidhogg remained wary, refusing to trust mortals after his brother Bahamut was slain by the Allagan Empire.
This peace was ultimately shattered, and Nidhogg's suspicions confirmed, when the Ascians revealed to the ishgardian King Thordan I the source of a great wyrm's powers—their eyes. With this knowledge in hand, Thordan and his Knights Twelve murdered Nidhogg's sister Ratatoskr and consumed her eyes. In a rage, Nidhogg attacked the mortals, and succeeded in slaying Thordan and four of the knights, but in the process Thordan's son Haldrath wrested Nidhogg's own eyes out of their sockets.
Forced to retreat and facing certain death without his eyes, Nidhogg met with Hraesvelgr. Refusing to give up on his vengeance, Nidhogg convinced his reluctant brother to give him his left eye, so that Nidhogg might live and rally the Dravanian Horde to continue his newfound war with Ishgard, which would become known as the Dragonsong War.
Nidhogg's own Eyes, however, would persist as powerful relics. The Holy See would cover up Ratatoskr's death and claim that Nidhogg had attacked them unprovoked as justification for taking his eyes. Rather than consuming them outright as they did Ratatoskr's, the Ishgardians would keep the Eyes and continually draw on their power. Notably, this power aided greatly against the dragons themselves. Even Nidhogg could be tracked and cowed when faced with his own Eyes. Haldrath would carry them on his person and gain the title of the Azure Dragoon, Ishgard's greatest warrior. This would not be without side effects. Nidhogg had a constant link to the Eyes, and as such would always know where they were, and could influence the Eyes' carrier.
This influence led to Haldrath's premature demise, as carrying both Eyes would worsen the effect, and Haldrath was ultimately consumed by Nidhogg's rage. Recognizing the danger of wielding both Eyes, the Holy See would only pass on the left Eye to Haldrath's successor as Azure Dragoon, burying the right with Haldrath and fabricating the story that Nidhogg only lost his left, such that no one would look for the other. The left would be passed down the line of Azure Dragoons for centuries in service of Ishgard, while the right rested with Haldrath, its power preventing the first Azure Dragoon's corpse from decaying.
The title of Azure Dragoon and the accompanying Eye ultimately fell to Ser Alberic Bale. When the Horde attacked the village of Ferndale, Alberic battled with Nidhogg himself. During the battle, Alberic wounded Nidhogg, but in doing so was nearly overwhelmed by the Eye. Choosing to abandon the power of the Eye rather than fall into its sway, Alberic succeeded in defeating the great wyrm. However, without the Eye the remaining dragons were mostly free to ravage the village, and Alberic succeeded in saving only a single child named Estinien.
Growing up with naught but vengeance against Nidhogg in his heart, Estinien would be trained by Ser Alberic himself and succeed him as Azure Dragoon, earning himself the surname Wyrmblood in his quest. However, Estinien's hatred for Nidhogg would leave him particularly susceptible to the Eye's influence. When the Eye showed him a vision of Ser Alberic's actions in Ferndale, Estinien railed against his mentor, accusing him of being a coward for forsaking the Eye's power and allowing Ferndale to be burned in turn. Alberic is saved by the intervention of the Adventurer, who had themselves been chosen as a second Azure Dragoon. Losing the duel against his counterpart, Estinien succumbed to the Eye's influence and called upon Nidhogg for the power to vanquish his foes. As he did this, the spirit of Haldrath appeared and attacked him, and they disappeared in a flash of light.
Estinien later resurfaced free of the Eye's influence, presumably thanks to Haldrath. Following the Dravanian Horde's most recent and most devastating attack on Ishgard, Estinien embarked on a quest with the Adventurer, now known as the Warrior of Light, in an attempt to parlay with Nidhogg's brother Hraesvelgr to stop or at least stall another attack on the city. Learning the truth behind the beginnings of the Dragonsong War and Nidhogg's rage, the party determined that Nidhogg would not stop while he drew breath, and set off for his lair in the Aery to put an end to the great wyrm.
Using the Eye's power against him, Estinien finally succeeded in slaying Nidhogg, and wrested his remaining eye from his socket. However, Estinien noticed something odd - he carried the left Eye of Nidhogg on his person, yet he just pulled an eye out of Nidhogg's left socket. In addition, the Eye he carried was red, while the new eye was yellow - not unlike Nidhogg's one-eyed brother Hraesvelgr. Confronting Hraesvelgr with this, the great wyrm reclaimed his missing eye and told them how it came in Nidhogg's possession. Realizing now that the Holy See was hiding the other Eye of Nidhogg, combined with the other ugly truths of the War, the party returned to Ishgard to expose the their lies.
The current ruler of Ishgard, Archbishop Thordan VII, and his personal guard, the Heavens' Ward, fled the city with Haldrath's coffin, and headed for the floating continent of Azys Lla. Having learned the secret to summoning primals from the ascian Lahabrea, Thordan hoped to use the right Eye of Nidhogg to consume the power of the imprisoned Warring Triad in order to himself become a primal powerful enough to single-handedly end the Dragonsong War. With Thordan possessing the only key to bypass the barrier surrounding the continent, Estinien used the left Eye to power an aetheric ram and destroy the barrier outright.
While pursuing Thordan into the Aetherochemical Research Facility, Estinien is forced to remain behind to hold off a Garlean contingent, and gave the left Eye to the Warrior of Light. The Warrior in turn used the power of the Eye to vanquish the ascian Igeyorhm. Before the same could be done to Lahabrea, Thordan arrived and retrieved the right Eye from Haldrath's tomb, and transformed into an immensely powerful primal named King Thordan, powered by the Eye, housed in the hilt of his sword Ascalon, and a millenia of prayer from Ishgard's faithful. Thordan destroyed Lahabrea himself, but is then defeated by the Warrior of Light.
With Thordan and Nidhogg vanquished, Estinien claimed both Eyes. Unfortunately, in his belief that the Dragonsong War would now be ended, he let his guard down and was fully consumed by the power of both Eyes. Such was Nidhogg's hatred that through the Eyes he was reborn in Estinien's body, now at full strength thanks to possessing both of his own eyes again. He then retreated to regroup the Dravanian Horde for another final assault on Ishgard.
When Nidhogg later resurfaced, he adopted Estinien's form as a means of mocking Ishgard, the Azure Dragoon so corrupted by the Eyes that they had fused to his body and he eventually sprouted draconic wings. Nidhogg is ultimately undone by the intervention of Hraesvelgr, who gifted the Warrior of Light one of his own eyes, which protected them from the full extent of Nidhogg's rage. The great wyrm once again defeated, the Warrior of Light and their allies pried the Eyes from Estinien's body and cast them into the valley below the Steps of Faith, finally freeing the dragoon from Nidhogg's grasp.
The Eyes would not simply disappear, unfortunately. Recovered by the Warriors of Darkness for the ascian Elidibus, he gifted them to the Griffin, an extremist Ala Mhigan rebel. The Griffin later used them, along with his own life and those of his followers, as catalysts in the summoning of the primal Shinryu. Shinryu takes on a draconic form based on both Nidhogg's eyes being the primary source of aether for its summoning, and the Griffin's desire to inflict another Calamity like the one caused by Bahamut.
Níðhöggr (meaning "malice striker" in Old Norse, commonly anglicized as "Nidhogg") is a dragon in Norse mythology who would eat the roots of Yggdrasil, the world tree.The