User blog comment:SayuriDarling/The Mark of Athena Official Discussion/@comment-173.64.122.195-20121004033234/@comment-5562903-20121004172722

About Nico's skin tone: I imagine him as follows;

Titan's Curse - tan-olive

Battle of the Labyrinth, Last Olympian, The Son of Neptune - pale, but still hints of tan-olive like he used to

The Mark of Athena - pale. Like paler than me pale.(And believe me, I'm as pale as a daughter of Hades...)