Pandemonium

Pandemonium is a plane of madness, a great mass of rock riddled with tunnels carved by howling winds. It is cold, noisy, and dark, with no natural light. Wind quickly extinguishes nonmagical open flames such as torches and campfires. It also makes conversation possible only by yelling, and even then only to a maximum distance of 10 feet. Creatures have disadvantage on any ability check that relies on hearing. At times the wind can be strong enough to pick a person off their feet and throw them against the rocks.

Gravity is oriented towards whichever wall is nearest. Most of the plane’s inhabitants are creatures banished here with no hope of escape who have been driven mad by the howling winds.

The winds on this plane make spellcasting difficult. If a creature tries to cast a spell with a verbal component, they must first succeed on a DC 10 Constitution saving throw, losing the spell slot and action on a failed save.

A visitor must make a DC 10 Wisdom saving throw after each hour spent among the howling winds. On a failed save, the creature gains one level of exhaustion. A creature that reaches six levels of exhaustion while on this plane doesn’t die. Instead, the creature gains a random form of indefinite madness, as described in chapter 8, “Running the Game.” Finishing a long rest doesn’t reduce a creature’s exhaustion level unless the creature can somehow escape the maddening winds.