Maaldoria

Maaldoria, also known as Slaver's Moon, is a planet in the Arcturus system home to the Maaldorians. The D.E.O.'s official designation for the planet is 51 ARC B. It orbits the red star Arcturus and is known as the heart of the intergalactic slave trade. Maaldoria's air is toxic to Green Martians due to silicates in its air. Diamonds are extremely common on the planet to the point where the locals think of them as dirt.

History
Maaldoria became known as the center of the slave trade in the galaxy and as such, was nicknamed Slaver's Moon. Before Daxam's destruction, Daxam's royal family used to come to Maaldoria to buy slaves. Maaldoria also sold slaves to the Dominators.

Roulette and a group of Maaldorians devised a scheme to use a transmatter portal to bring unsuspecting humans from Earth to Maaldoria to sell them into slavery. However, Supergirl and Mon-El discovered the plan and used the portal to go to Maaldoria but due to its red sun, were stripped of their powers. With the help of Alex Danvers and the D.E.O., they intervened and were able to evacuate the human captives from the Red Fortress back to Earth.

Former residents

 * Jo Gunraf

Behind the scenes

 * Even though it is called "Slaver's Moon", multiple characters referred to it as a planet, not a moon.