They say Chuck Norris can stare a man to death. But with Rinji, it's quite literal. If you see his right eye doing this, consider yourself a dead man. You will be on fire, a special kind of black fire, and you will burn. No water, fire extinguisher, or any other flame retardant can make this fire go out. It will continue to burn whatever it touches until it is reduced to ashes.
Of course, Rinji must use Amaterasu sparingly. Because as you can see, it doesn't agree well with the eye that casts it. And using it will only accelerate the loss of Rinji's eyesight. So this is pretty much a double edged sword for him. So even though it puts a terrible strain on his eyes, namely his right one, Rinji is someone who can literally stare you to death.
Art by Kodriak