Prison of Alien Dimensions

As the firelight gradually died, Sharen stared tensely at the convulsing back of the aberrant chieftain in the frigid cell. The next moment, the chieftain abruptly turned around, hooked his fingers into his eye sockets, and slowly lifted off his own skullcap.

"I shall grant you new insight."

Overjoyed, Sharen hurriedly took out the forbidden grimoire hidden within his eyeball, eager to share his own knowledge in return.

Seconds later, the mind-shattered aberrant chieftain crawled from the cell with tearful wails, then sprinted through the arcades as they gradually collapsed into endless darkness...

The short version: This is a death game where lives are the wager-and a carnival for madmen pursuing forbidden knowledge. Terminally ill Sharen chooses to join this feast of maddening nightmares in order to cure his incurable disease.