All Seeing Eyes of God

The All-Seeing Eyes of the Gods (神々の義眼) is an artifact given to Leonardo Watch by Riga El Menuhyut in exchange for his sister's sight prior to the beginning of the series. Though largely a mystery, the eyes are a prime artifact even throughout the alterworld and are incredibly valuable, thus many people will go after them no matter what it takes.

History
Prior to Leonardo Watch, there have been at least 53 other confirmed records of the All Seeing Eyes of the God holders in both the human world and the alterworld. In all instances of people receiving the eyes, the person closest to them has their own vision taken away. Riga El Menuhyut only appears to give the All Seeing Eyes of God to humans when a major cataclysm occurs in the human world, such as the advent of Hellsalem's Lot, in order to record them.

Description
The holders are chosen as the observers of major world-changing events, willingly or otherwise, and a contract is made between the holder and Riga El Menuhyut. In exchange for the eyes, the person closest to the holder is blinded. This serves as both a sacrifice for the manifestation of a divine miracle and as an anchor to keep the holder of the eyes in check, so that they cannot act rashly and can only observe obediently in the stead of the celestial beings.

As it is the result of a contract with a celestial being, removal of the All Seeing Eyes of God is not as simple as going through a surgical procedure, and the eyes cannot be cured or returned to what they were before. Doing so would be the equivalent of forfeiting the contract made, and a price would have to be paid for such an act.

Powers
Holders of the All Seeing Eyes of God are able to see the 'The Truth' of the world. Possession of the eyes gives their wielders numerous abilities including heightened visual senses, allowing them to see fast movements normally impossible for human eyes to follow, or minute details with great clarity, and allows them to gaze into both the past and the future. They are able to see past world altering illusions and perceive an individual's unique aura, including the scarlet feathered aura of a Blood Breed. Observing an Elder Blood Breed for a set duration can also reveal their "true name" if its heart is present.

Eye holders are capable of altering and controlling the vision of those around them, such as switching two people's field of vision, inducing nauseating hallucinations, projecting what the holder sees into the minds of others, and the power over visual illusions in general. The eyes also allow the holder to see through another individual's eyes and observe past events that they have witnessed. The eyes are also equipped with a self-restoration function such that over time, they will heal themselves of any damage sustained.

Using the eyes however has its limits. Due to the huge amount of visual information that the eye holder's brain has to take in, it takes weeks for the holder to get used to them after they are first implanted. Furthermore, prolonged use of the eyes' abilities causes them to overheat and begin to burn the holder. If the eyes sustain enough damage that they crack, the cracked eye's powers cannot be used until they heal. However, physically damaging the eye beyond repair will cause the eye to explode, killing the holder.