Red Fire

Red Fire was the prize for the Completionist challenge: finish every other challenge of the Christmas Event 2017 and the knife was yours. It was never a box drop and never a tier purchase, which makes it different from its green twin. The event is over, so trading is the only route now.

Completing the list

The wiki phrases the source as completing all of the challenges during the 2017 Christmas Event. Because the reward depended on finishing everything else first, owning the knife meant a player had worked through the entire event. The curated data dates that Christmas Event from December 25, 2017 to February 27, 2018.

Appearance

The blade is red and fades into a lighter shade, with a fire texture imprinted over it, which gives the knife its name. The guard is red as well, and the handle is solid black. The layout copies Green Fire exactly, only in a different color.

Fire Set

The wiki mentions a green variant under the name Green Fire, which came from the 2017 Christmas Box. The two are the Fire Set, with one half earned through a challenge list and the other pulled from a box.