The infinity blade made its debut as the first sword in Fortnite during Season 7. The blade is incredibly difficult to stop and gives its holder the ability to move quicker, increased health (both shield and regular HP can be charged to 200), and an attack that deals significant damage to other players. As of today, breaking structures with the infinity blade allows you to harvest material. Rumor has it Epic Games is expecting to nerf the blade and will turn off the ability to harvest material with structures broken using the blade.
*December 14 UPDATE, Infinity Blade removed from game*
Per Epic Games Fortnite Twitter, the Infinity Blade has been removed from the game due to it being overpowered. The following information on the infinity blade is no longer valid.
The blade is found south of the main castle at Polar Peak sitting in the courtyard. When the blade is first picked up, it takes 5 seconds to remove it from the ground and your character is vulnerable to gunfire (or being pickaxed) at this time. This area is incredibly busy at this time due to the popularity of the blade, so don't expect to be able to walk up and grab it without putting up a significant fight.
Courtyard in polar peak with the infinity blade.
When picking up the infinity blade, you lose the ability to use any other weapons or shields that you were currently holding. The blade itself has two different attacks that can be performed. By pressing the right trigger (for the main attack), you will swing the blade and any player in its path will be dealt 75 damage. By pressing the left trigger (for the alternate attack), you will lunge and jump forward with the blade. When the blade hits the ground, any player in the immediate area will be dealt 25 damage. The lunge attack is great for moving quickly and dodging gunfire.
One of the things that makes killing the infinity blade holder so difficult is their movement speed increase. Holding the blade gives you an 130% increase in your movement speed. In addition to this, the infinity blade holder can utilize the lunge attack to move even quicker. Doing so makes it very difficult for opposing players to get accurate shots on you!
Holding the infinity blade increases your regular HP and shield to 200 each. Every second you will also receive 1 HP, so if your health has run low you can hide to regenerate health. Killing an opposing player will also give you an additional 50 HP.
Player utilizing the Infinity Blade with 400 total HP.
At this time, the infinity blade is in all regular game modes (solos, duos, and squads). This differs from Epic Games' prior release of power weapons (ie. Thanos event) that were exclusive to their own unique game mode. Only time will tell if the infinity blade is here to stay however.