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 have to get your hands on the hidden back accessory, which you can find north of Steamy Stacks.
Map
The back bling rests against one of the large rocks in the creek. Notice that it's easily visible and it's the same colors as your Sorana skin.
We recommend completing this challenge in Team Rumble mode, as it will help you avoid eager opponents early in the game.