Zeshin and Bun's unnamed planet is a spring-mint green-like planet that was inhabited by an unnamed human-like, humanoid extraterrestrials that were conquered by the Frieza Force which was led by Cui and a couple of other Combatants when their planet was invaded by the latters' group before they had escaped from total extinction.
Only a handful of children from this planet had managed to survive by escaping with an invisible spaceship built by their parents/adults of their race which they use to wander in space and reach a planet of their race's trade partners who committed to help them. Many other children had fled in spaceships as well but were hunted down by Cui and his men.