Silver eyes begin as the (non-silver) eyeballs of a special breed of hyena from Lospass Island. When placed in the eye socket of a human being (consistently shown to be the left socket), they have the potential to silverize, which grants the human supernatural powers, most prominently immortality and youth. The full extent of the powers and mechanisms of the silver eye is unclear; it is stated in Flower, Sun, and Rain that two silver eyes in the same place invokes the "will of God" which warps time, for example.
Silver eyes were originally utilized in ancient Sundance Tribe rituals. In the events of the Silver Case, Japanese politician Uminosuke Hachisuka acquired a silver eye from a Sundance man, Format Kamui. The Shelter Kids Policy was put into place partially as an attempt to manufacture more; however, it never succeeded, and all hyena eyes in the program failed to silverize.
List of known silver eyes
- Format Kamui had a silver eye inserted into him at the age of two. This eye was later stolen by Uminosuke Hachisuka, and even later stolen from him by Tokio Morishima. This eye was seemingly taken from him before the events of The 25th Ward: The Silver Case.
- Tetsugoro Kusabi had one as Peter Bockwinkle. It's unclear if he kept it afterwards, or if the eye was ever put into Kusabi's actual person; it is possible it was only a part of the Bockwinkle disguise.
- The bomb-fitted clone of Step Sding seen in Flower, Sun, and Rain had one before he exploded.
- According to Famitsu interviews, Catherine has a silver eye in its core, though Sumio Mondo is not aware of it.
- Yotaro Osato appears to have two silver eyes.
- Sundance Shot has been strongly suggested to have had a silver eye at some point, though now he wears an eyepatch.
It's entirely possible that some of these silver eyes are one and the same, having moved hands at some point, especially seeing as Sundance may have had one that is no longer there, and the various instances of plugging into eyes that Catherine performs.
In art on the cover and at the beginning of Pre-Lunatics, Ryo Kazan and Kamui Fujiwara are both drawn with silver eyes, but they do not have them in canon, with Ryo's eyes being drawn normally in the comic itself.
Allusions to silver eyes
There are also instances in which the concept of silver eyes is alluded to but is tantalizingly not mentioned.
- Kevin Smith's eyes have a reverse coloration that makes them resemble silver eyes. Hand in killer7 states, "In the dark, his eyes are supposed to shine. However, this has not been confirmed." There are many other suspicious points about Kevin that seem to compare him to Kamui or Shelter Kids (liking dark places, not speaking) but the truth has not yet been confirmed.
- Uehara's eyes are complimented at one point by Aoyama. In Travis Strikes Again: No More Heroes, more characters make comments about Uehara's eyes, culminating in his left eye glowing with power, but whether he has a silver eye itself is not known. (Speculation: if he is a Shelter Kid, it is possible that he had a dormant hyena eye left in him that didn't silverize until later.)
- Travis Touchdown is conspicuously drawn with a scar over his left eye starting with Travis Strikes Again, but how he got it has not been addressed. In a trailer for No More Heroes III, the camera zooms into Travis' right eye instead, within which is silver and red particles.
The left eye glowing with power or otherwise being different as a basic concept is also referenced in numerous other works, such as Killer Is Dead, Short Peace: Ranko Tsukigime's Longest Day and more.