Questions regarding the history and physiology of StarCraft 2's ever-warring factions have been answered in a thorough, lore-focused interview with co-lead writer Brian Kindregan on Battle.net.
According to Kindregan, zerg have adapted to travel through space without oxygen, shields or armor, and a race that can adapt that quickly to not need tools is a foreign idea to humans.
"The question of how they can do things without tools is a uniquely human way to look at a problem," he said. "When we can't do something, we build a tool to do it for us."
Kindregan explained how the zerg Overmind developed his vision of destroying the humanoid protoss race. He explains that the Overmind's consciousness was shaped by the Dark Voice, a malevolent presence within the Void of space.
"During that process, the Overmind was exposed to some of the Dark Voice's plans for the future," Kidregan explained. "Scattered, confused images, sensations, ideas, concepts. Nothing clear or concrete. That vision was a narrative the Overmind constructed from bits and pieces, and it was about all that the Overmind could glean from the time spent with the Dark Voice."
The writer also noted that zerg are capable of performing any actions their overall leader performs, but that the Swarm likely would never become compassionate towards the protoss should the zerg cease their quest to destroy the protoss race.
"But why would the leader of the Swarm ever want or need to show compassion?" he said. "Compassion would not serve to grow the Swarm, and it's unlikely any race would ever accept the Swarm as allies or equals."
StarCraft 2: Heart of the Swarm, the game's latest expansion, is currently in beta and will be released on March 12.