This occurred before the dawn of the cosmos, when the universe was empty and was known as the Nothingsea. It is not known what Gmork did during this time before he was found by the goddess Vawk, who is a key figure in the Kroot's faith. At that time, she had been wandering the Nothingsea alone for countless ages and was delighted to meet another god. Vawk approached Gmork with an offer of friendship and suggested they should work together to discover other gods. The Destroyer laughed at this idea and attacked her instead. Thus began the Battle of Nothingsea, and the blows they threw at each other were so powerful that the Nothingsea began to tear and stars and worlds began to be born. This delighted Vawk, as it was in in accordance with her Great Plan to cause the birth of the heavens, but Gmork sought to destroy the newly born universe. A despairing Vawk tried to stop him, but they were evenly matched, until in a great rage she plunged her beak into Gmork's neck. The Destroyer's god-blood filled her gullet, and while the goddess spat most of the repulsive blood out, a drop managed to go down her throat. This caused a great sickness to spread throughout Vawk's body, but it also gave her Gmork's strength, and she defeated the Destroyer. After banishing Gmork to the regions of the Nothingsea still clad in darkness, Vawk realized that his god-blood had fatally poisoned her. With her life coming to an end, Vawk singled out the world right at the center of her Great Plan, called Pech, and landed on its surface. Before the goddess died from the god-blood poison, Vawk used her final breath to vomit out a great flock of eagles into the sky, which gave rise to the Kroot.
The Kroot tracker Dahyak Grekh told this creation myth to the Rogue Trader and Xenologist Janus Draik, who researched the battle. According to Draik, the name Gmork was clearly reminiscent of Ork, possibly linking the Greenskins to the Kroot. He therefore surmised that the Battle of Nothingsea was likely a mythical reference to an early encounter between the Kroot's ancestors and an Ork invasion.