The user of these eyes has their irises go red, and a skull appears in the middle of their eyes, reflecting the ability of the eye.
Using the Hissatsu no Me allows the user to see into their victim's body like an X-Ray, pointing out any structural defaults or muscle deformities in the opponent. Not only that, but use of the eye can give the ability to see weaknesses in their opponent's style of attack, and the user can predict the opponent's movement vector to a degree. If the user focuses in on their opponent enough, time appears to slow down for them.
The user must kill someone each time they use these eyes, or go blind.