It appears as though Fortnite is currently allowing Xbox One gamers to play alongside PlayStation 4 players via cross play functionality.
Note that the person who killed the PS4 gamer has the Gamertag titled ‘zCypher Nine’, which isn’t possibly a PSN Gamertag, seeing as Sony don’t allow for spaces in your name. If however you move to the Xbox One and search for the user, not only will you see a well established Gamertag, but one that has actively been playing Fortnite. We also checked to see if this tag was possibly a PC tag that was using the Epic Launcher, and again, it’s not a Gamertag that’s in use on that platform either.
It’s a bizarre situation to say the least, but it’s highly likely that this is just an error on Epic’s part. With Sony categorically being against cross-play between PS4 and Xbox One, we don’t suspect that this feature will live (if indeed true) for much longer. We’ve reached out for comment and will of course keep you in the loop.