What are the Three Harm Challenges in Fortnite?

The three harm challenges in Fortnite are just what Marvel fans ordered as Epic Games has now confirmed that Marvel will be crossing paths with Fortnite yet again. All the fan speculation over the past few months have been leading to this gaming moment and it is unlike any other we have seen before.
By playing through and completing the Marvels Avenger Beta you should unlock a room aboard the helicarrier known as the HARM room. It is there that you will then navigate through the menu and complete the 3 challenges required to unlock your reward in Fortnite.
The Herald has found The Island.
— Fortnite (@FortniteGame) August 22, 2020
The prelude to War has begun. Experience Part 1 in-game now...#FortniteSeason4 8.27.2020 pic.twitter.com/Pl14rHYjGq
What are the Three Harm Challenges in Fortnite?
The three challenges you have to complete are surprisingly not in Fortnite, they are actually in the Marvel Avengers Beta, and once completed the rewards will then transfer over to Fortnite. All you have to do for the three HARM challenges is to survive and fight your way through waves of enemies. Note that enemy difficulty does increase from challenge to challenge. If you find yourself in trouble try to level up your Avenger by doing other side missions, because you are only given a certain amount of lives or you would have to start from square one again.
Once all three HARM challenges are complete you will then be able to earn your rewards. One being a customizable nameplate for the full Marvel Avengers game and the other being the Hulk fists for Fortnite.
To receive your Hulk fists you must link your Epic Games and Square Enix accounts. Once that is out of the way hop on Fortnite, go to your pickaxe load-out section and Hulk smash your way to victory.