This object is a magic brainwave explorer.

Coastal Theater.

I showed the adventurers the cylindrical machine and helmet.

This explorer has a test I made. Your mana and blood will drive the magic circle, and if you successfully explore here, you will pass. If you fail, you wont be allowed on the island.

This brainwave explorer was a high-quality object, but now that I applied Midas Hand, it was sufficient to create a completely new world from ones unconscious.

Its simple.

Therefore, the test of mental power was straightforward. Participants entrusted their consciousness to this machine. When the test subject internally consented to their mana and signed the magic circle with blood, a phenomenon similar to Carlas Authority would occur. To be precise, it was an imitation of Carlas authority, but, well, anyway.