The Eye of Truth is a magical object created with the power of the Druthulidi Dethl.
History[]
First Golden Age[]
When the demon of nightmares Dethl arrived to the dreadful Shadow Temple, the Sheikah were quick to contain it and use its power to create incredible artifacts. One such object was the Eye of Truth, something imbued with the dark powers of the demon, as well as its madness. Though capable of great things, its use had to be limited, otherwise the user would fall under the influence of Dethl. Even after the abandonment of the Shadow Temple, now overrun by undead abominations, the cadre would still utilize the Eye of Truth.
Rise of Ganon[]
Bongo uses the eye on Nohansen
When Dethl desires a fresh source of nourishment after hundreds of years feeding on the Shadow Temple's prisoners, it decides to haunt the dreams of Bongo, the current holder of the Eye of Truth, impressing the need to visit the Shadow Temple. Bongo eventually manages to enter the Shadow Temple with the help of Ganon, though Dethl is taken by surprise by the army that is brought in with them. Dethl attempts to stop Ganon's army with hordes of ReDead and other twisted denizens of the haunted prison, but Ganon's army is able to fight their way through and injure Dethl. Before Ganon and Bongo are able to leave the Shadow Temple, Dethl slips into Bongo's mind and escape.
Bongo, possessed by Dethl, uses the eye on Sil Rhoam Bosphoramus and discovers the location of the Triforce at the Water Temple. After Bongo's death, the Eye of Truth is recovered by the Sheikah and stored within a highly-protected reliquary.
First Golden Age[]
The Eye of Truth is eventually stolen by the Sheikah wizard Agahnim for his own ends. When his marriage to Marhala Nohansen Zelda III is annulled and he is exiled as a result of the discovery of his Sheikah blood, Agahnim uses the Eye of Truth to erase the knowledge of this marriage and installs himself back into the Hylian government.
Gerudo Wars[]
In the Gerudo Wars, after the fall of Hyrule Castle, Agahnim uses the Eye of Truth to make Hylian soldiers serve him. It is possible that Dethl might have tried to influence Agahnim through the Eye of Truth, but Agahnim's devotion to the demon Majora renders Dethl's nightmare influence useless. When Impa leads an army of loyal Sheikah to retake the city and executes Agahnim, the Hylian general Akazoo comes into possession of the Eye of Truth.
The Return of Sulkaris[]
Exploiting Akazoo's envy over being denied marriage to Princess Oraiya Zelda IV, Dethl, through the Eye of Truth, accelerates his insanity until he betrays the Kingdom of Hyrule by unleashing a swarm of Gohma upon the town of Malkariko.