Black Knight is an outfit in the Fortnite Battle Royale game, with a red ribbon.
“The odious scourge of Wailing Woods”
It is a part of the Fort Knights Set.
How to get
It is also a premium tier 70 Battle Pass reward.
You need to buy the Battle Pass and make it reach Level 70.
However, as of February 22, 2018, the costume is not available anymore when Season 3 began.
Black Knight is considered the final prize of the premium Season 2.