It's fashionable in his time and place for persons to have color changing features. You see it most often with the hair, of course. Young people love being able to change their brightly colored locks, at an instant, to match their wardrobe. The same tech exists for the eyes and even skin color.

The thing is, though, that even in a place where people can modify the color of their eyes at will ... you don't see yellow very much. It's rare enough that Zero takes notice of those bright eyes looking at him. 'They're somewhat predatory looking in a human', he muses to himself.

"Your answer ... c'est terriblement littérale, non?"

Zero is wrapping his mechanical index and pointer finger around a mid-knuckle joint that will never pop again. He's only ever trying to crack his mechanical hands because it still feels good in a way that he can't explain.

"Speaking on your genetics, though, have your eyes always been yellow?"