This challenge closes the great event mission Alter Ego. To access it, you must first have completed all the standard missions proposed and collected all the letters composing the word "Fortnite".
Once dressed in the legendary Sorana outfit — that finishes the Alter Ego challenges — you'll need to get your hands on the hidden pickaxe, which will be found in the snow-covered heights to the southeast of the map.
The pickaxe lie not far from Mount Kay — which is the highest peak on Apollo Island.
You can land on the summit and then descend following the red flags that serve as a landmark for climbers. The pickaxes is located just next to one of the flags, slightly below.
We recommend completing this challenge in Team Rumble mode, as it will help you avoid eager opponents early in the game.