Excalbia

Excalbia is a planet located near Federation space. The planet is mostly molten and is the homeworld of the Excalbian race.

In 2269 Excalbia was the site of an experiment on the nature of good and evil conducted by Yarnek with the unwilling participation of the senior officers of the USS Enterprise. Yarnek recreated several historical figures thought to embody the concepts of good and evil and pitted them in combat against each other before the Enterprise crew was allowed to depart. (TOS: "The Savage Curtain")