El Dorado

Golden City El Dorado (黄金郷エル・ドラード) is the country ruled by Demon Lord Leon Cromwell, located on another continent larger than Australia on earth.

Overview
It is wide and has towns divided into districts. Forest, Field, Lake, River, and Mountain districts. Every sector is protected via a magic circle. An artificially created land of nature and tranquility–a magic city.

There's a gigantic active volcano in the center of the continent, emitting smokes and flames throughout the year. The beautiful capital and Leon's palace was built nearby, but volcanic ashes and smokes never falls into the city thanks to magic airflow manipulation.

One of the hell gates also happens to be situated near the capital, which was where Carrera manifested herself and attacked the city from, before she pledged her loyalty to Rimuru.

Trivia

 * Leon seems to have named his country after the legendary city of gold. Which is Spanish for "The Golden One".