http://www.newsweek.com/fortnite-skull-trooper-challenge-guide-how-get-purple-new-colors-1162048

Fortnite update 6.02 includes the Skull Trooper challenges, which offer a chance to customize the skin using the Ghost Portal Back Bling. Want to make your Skull Trooper blue, green or purple? Here’s what must be done.

The Skull Trooper is available now in 'Fortnite's Item Shop. Epic Games