The Zehoberei, or Zen-Whoberi are a green-skinned alien race. The Zehoberei are the inhabitants of the planet Zen-Whoberi. Due to overpopulation, poverty and starvation were a commonplace issue across the planet, so much that the planet became an early target of Thanos.
The warlord obliterated half of the Zehoberei species, since which its remainder, according to Thanos himself, has lived in prosperity due to issues like poverty and wasting of resources becoming non-existent with a smaller population.
Gamora was taken in during Thanos' attack as his adoptive daughter and trained as his assassin.