Silver eye

Tokio Morishima with a silver eye in his left eye socket in Flower, Sun, and Rain.

The silver eyes are very important objects in the world of Kill the Past. They were first introduced in The Silver Case and have been mentioned or alluded to in most subsequent works.

Silver eyes are the 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.