You can get special Fortnite rewards by playing the Marvel’s Avengers beta, but you won’t get anything if you don’t link your Fortnite account. Like most Fortnite crossovers, you have to link your Epic Games account in order to receive your in-game rewards. Your Epic Games account may already be linked with most services like PSN or Xbox Live, but you need to link your Square Enix Members account in order to get your Hulk Smashers pickaxe and Hulkbuster style from the Avengers beta.
After linking your accounts, you’ll have to play the Avengers beta to receive your Fortnite rewards. To earn the Fortnite items from the Avengers beta, you must complete all three HARM Room challenges available in the beta. These challenges pit you against waves of foes that get increasingly stronger, but you should be able to finish them fairly quickly in multiplayer with some friends.
Once you’ve successfully completed the challenges, you’ll receive a notification in the Avengers beta that your Fortnite rewards are waiting for you. At that point, all you have to do is log into Fortnite and you can find your Hulk Smashers pickaxe and Hulkbuster style in your inventory. They’ll show up in the item shop at a later date, but you can get them early for free by playing the Avengers beta. Make sure you link your accounts using the steps listed above though, or else you won’t get your rewards.
World news – GB – Avengers Beta – How to Link Your Fortnite Account | Attack of the Fanboy