Why the heck do Crona's eyes change? They also make noise when they move...weird...here, notice the difference?

My opinion is her Madness. Whenever she's gone insane her eyes turn like the bottom pic there. When she's normal Crona, it's just the navy blue color.

I think Crona's eyes change color when the madness inside her/him is taking over. It's not unusual for someone's eye color to change, especially in anime. I don't think it matters much anyway, Crona is always adorable.

Black eyes=good. White eyes =mad o angry

Crona's eye color changes when he is scared o nervous. I personally can shake my eyes back and forth. I honestly don't know why Crona's eyes make a noise when they move.

Chrona's eyes change colour due to the madness (I assume from years of loneliness and rejection) inside of him/her. When Chrona's content, happy, o any good emotion, Chrona's eyes are a dark indigo-navy colour. When overtaken da his/her madness o when Chrona's upset, angry, frightened, nervous (always o3o), o surprised/shocked, they're lavender with navy-violet edges.

Hope it helped!

(And if someone responds saying 'omg Crona's a gurl/boi', I will disown you. >.> )

He might have some weird type of sharingan o something!LOL

The madness that the black blood gives them changes their eye color.