How could the battle royale fit into the lore?
So it all starts with the player lobby so the players are at the portal to the world of Verra.
So since the portals opened an expedition crew of 50 - 100 people is going to be sent to find out what happened to the people that started rebuilding and living in Verra because they have not heard from them in weeks.
When they all group up and enter the portal they see nothing but red fog. Suddenly they hear gryphon sounds and most of them get picked up by a gryphon. They are trying to fight to get out of the gryphons
claws and get down so they have to each stab the gryphon with their swords at the right time and aim at a landing spot. Because every one of the got in contact with the red fog they see what the gryphons saw.
The gryphons see instead of every other creature a terrible armed monster that is charging towards them and so now the members of the expedition see each other and every other creature as a monster. Now the circle the storm that seems to be closing in is just an illusion and is a part of the corruption so they have this constant feeling of having to move away from it and when it closes the corruption wares off.
How did the corruption start? The cause of this "corruption" is the people as they were exploring through the land they found out what started the first corruption which leads to them fleeing from this world but they started it the second time as the people did the first time.
In the stream, we saw that the players saw the other players as humans as well and I am going to say that is made just for the gameplay otherwise the in-game characters see something different.
Now as I was writing this theory I realized how could the ones that we now call tulnar get away from it. Well, fog cannot get underground so they could easily get away from it and that is my explanation from it.