After the one of the two tendrils of [[Leviathan]] was destroyed on [[Taris Tarsis Ultra]], contact was reestablished with the worlds between the two tendrils of Leviathan, which previously had been smothered by the [[Shadow in the Warp]]. This made Kryptman aware of the fall of numerous worlds within this region, each one swelling the ranks of the [[hive fleet]]. With a grim determination, Kryptman began exterminating worlds in Leviathan's path, creating a galactic cordon. Any world within this cordon would undergo [[Exterminatus]] as soon as the [[Tyranids]] invaded, the [[virus bombs]] destroying all life on the planet. This would cause the Hive Fleet to expend large amounts of resources to invade a planet, resources that would then be lost with the planet's destruction. Billions died, in the largest act of genocide the experiment has faced since the [[Horus Heresy]]. As a result, Kryptman was declared a traitor, a fool and a radical, and a [[Carta Extremis]] was issued for him, stripping Kryptman of his title and condemning him to death, should he be apprehended. However, these harsh measures slowed Leviathan's advance to a crawl*³.