The concept of a 'third eye' has existed in popular culture for a long time, albeit as a metaphor for various things. The earliest known Augmentation users took advantage of this aetheric framework and subsequently created an entire family of Augmentation spells centered around the generation of a third eye.
The primary purpose of a Third Eye is to enhance an individual's aethersight, either providing the ability where none exists or increasing existing aethersight in power or clarity. However, the specifics of the enhancement are subtly different for each type of Eye.
True Vision Edit
The Eye of True Vision is the simplest and most direct form of Third Eye, mostly used for those with weak or nonexistent aethersight (thus its name). When in use in conjuction with normal vision (optical or otherwise), it creates a faint overlay of aethersight, allowing the detection of aetherically active entities through any sort of physical obstruction. In the absence of normal vision, the Eye allows detailed basic aethersight with a few seconds' depth in either direction of time, and is effective in this capacity up to about 25 meters or so; beyond this range, the time depth ceases abruptly and the fine detail begins to fade, the aethersight itself becoming useless at around 100 meters out.
The Eye of Foresight is a Third Eye specifically designed for future-centric aethersight. It is only useful in the absence of normal vision, and allows the observation of the most likely near-futures in a 25-meter radius up to a maximum of ten minutes. More divergent possibilities tend to be less observable even under the ten-minute limit. If desired, the future depth can be decreased to near-zero, allowing this Eye to be used effectively as close-range standard aethersight.
The Eye of Hindsight is a Third Eye specifically designed for past-centric aethersight. It is primarily of use in investigations or near-misses, or any other time a clear and (usually) unbiased record of past happenings is required. Like the Eye of Foresight, it is effective up to a 25-meter radius; unlike that Eye, the Eye of Hindsight may be extended to view several hours' worth of past events, since there are no alternate possibilities to sort through. The past depth can also be decreased to near-zero, once again allowing for effective close-range standard aethersight.
The Beast Edit
The Eye of the Beast is a combat-purposed Third Eye specifically designed to detect movement. It dims the aetheric pattern of anything under a certain threshold of movement, though it will catch the expansion of a Zone for a spell that is about to be cast. Like the other Eyes, it has an effective 25-meter radius, making it best suitable for close quarters or urban combat.
Providing an individual with a Third Eye is, like all Augmentation magic, a delicate process that essentially combines spellcasting with surgery. Unlike some other processes, Third Eye generation is most effective when the patient is at least partially conscious to allow for a much smoother transition; a Third Eye is immediately active once it is fully formed.
For an Augmentor who has practice in accessing the aetheric framework, generation of a Third Eye should only ever take 30 to 60 minutes. Less experienced casters may take several hours to ensure that everything is done properly and sufficiently.