So Nyx has eyes that change colour depending on her mood -which is why she wears sunglasses or masks most of the time.
Here is a chart showing some colours to match her mood.
(I didn't know how to make the images smaller...Sorry about that!)
Vengeance (or after she has killed)- Red
Excited/Energetic- Electric Green
There's more that'll pop up in my fanfic, but for now, that's it to the beginner's guide to Nyx's eye pallet!
Thanx for reading!