How do you tell story in a battle royale? Fortnite cannot lean on cutscenes and audio logs (although Fortnite will absolutely also break its own rules and use cutscenes and audio logs). It has brief lore snippets attached to its characters and items. It has environmental storytelling and live events. But, smartest of all I think, is its ability to have players act out parts of the story it wants to tell.
Take last week, for example, when Fortnite flipped the switch on a new Star Wars collaboration and parked a Star Destroyer over its island map. At the same time, an Imperial Stormtrooper skin appeared in Fortnite's in-game shop which countless people immediately forked out for (hello). Suddenly, lobbies were full of Stormtroopers - a genuine Fortnite invasion as if from the Empire's looming spaceship in the sky above. The game put these pieces in place, but it was its players that ended up roleplaying it for everyone else.
How about a less marketing-driven example? Back in Season 5 - the Road Trip season with Drift and Brite Bomber dubbed "Worlds Collide" - rifts brought all sorts of new things to the Fortnite map. But as the island filled up, a fleet of masked time cops named Enforcers dropped in to sort it all out - like the Reapers in that Christopher Ecclestone episode of Doctor Who.
The Enforcer was Season 5's secret skin - so of course as soon as he could be unlocked, lobbies were filled with him too. It meant you had players still playing as Drift and Brite Bomber being terrorised by this flood of Enforcers - just as that week's loading screen depicted.
As Fortnite tells a weekly narrative through loading screens, you can rely on seeing the characters they depict turn up in matches. Players like showing off the latest skins they've unlocked or purchased, of course, but they are also sometimes required to use them to fulfill in-game challenges and role-play certain parts of the game's storyline. Remember in Season 7, when you unlocked the Prisoner secret skin the week he was shown breaking out of the Ice King's dungeon? Subsequent weeks saw you power him up by recreating his various actions on further loading screens, until he reached his full, end of season volcano-summoning potential.
And in this season, in Chapter 2, Fortnite is subtly asking you to pick a side. Maybe you have the friendly Slurpman Rippley as your teammate, and you live out the fiction of fighting alongside the new team of E.G.O heroes. Or maybe you prefer being one of the baddies building up their genetically modified A.L.T.E.R. clones? Battle Pass skins have a version for each side, so you can roleplay who wins - at least until Fortnite's narrative moves on to whatever's next in store.