The Gargantis proximae are or were semi-intelligent space-faring organisms whose homeworld is still not known. Unlike most other species which were forcibly inducted into the Zerg Swarm, the Gargantis proximae - which were facing starvation at the time of their assimilation - willingly gave themselves to the Swarm in order to avoid extinction. This assimilation process was exceptionally successful, and the Gargantis proximae soon became known as the Overlords, one of the highest-tiered Zerg strains in existence.