Rigel looked at the big city in the desert where the Players gathered. He thought he could do the same thing on the 11th floor, but who would have thought those Players were already fighting each other? Everyone wanted to take over each floor and become the ruler just like the 3 Major Guilds used to be.
He manipulated the weather, turning it into a sandstorm, and yet the Players didn't bother by that. They thought it was a natural phenomenon, and the sandstorm wouldn't bother them that much because they were Players.
The longer they fought in the sandstorm, they began to feel stings on their bodies. They didn't realize the grains of sand had cut their skin and flesh. Once they realized it wasn't a normal sandstorm, it was already too late because they couldn't leave as the storm got fiercer and worse.