In time, it became a pack leader and became immense both in power and physique. By the time the Swarm and a deinfested Sarah Kerrigan returned to Zerus, it had been millennia since Zurvan's last evolution. Brakk was a primal Zerg pack leader on Zerus. When Sarah Kerrigan arrived on Zerus, Brakk declared that her Zerg intruded on his territory. Wishing to stop her from waking Zurvan, he sent his pack to destroy the quillgor meat that her drones were harvesting. When this was unsuccessful, he personally led an attack on her hive cluster and was killed. The remnants of Brakk's pack were destroyed shortly afterwards by Yagdra's pack. Kraith was a primal Zerg pack leader on Zerus and leader of Kraith's Pack. According to Zurvan, Kraith was "immense and consumed by hatred". Kraith was defeated by the new, primal reinfested Sarah Kerrigan, who consumed his essence. He was shown charging at a herd of Primal Zerglings, eliminating them. Slivan, the Eternal Mother was one of the primal Zerg pack leaders of Zerus. She was described as "hollow and destructive" by Zurvan. Slivan was defeated by the new, primal Queen of Blades, and her essence absorbed. She can spawn countless locusts. Yagdra was one of the primal Zerg pack leaders of Zerus. Yagdra closely resembled an ash worm in appearance, and it was considerably larger in stature than most other primal Zerg. It could spit gobs of destructive acid that burnt like fire. When Yagdra learned that Sarah Kerrigan was transforming in a chrysalis, it attempted to halt the process permanently by sending its pack at Kerrigan's brood. In the process, Yagdra also eradicated the last remnants of Brakk's now-leaderless pack, however, it was not successful in killing the Queen of Blades before she hatched from her chrysalis. The opportunity came soon enough, however, when Kerrigan, now the Primal Queen of Blades, set out to challenge the pack leaders for control of Zerus. She came for Yagdra first. Aided by Dehaka's Pack, Kerrigan fought her way through Yagdra's minions and confronted the pack leader himself. Yagdra told her that her transformation meant nothing. The two fought, and Kerrigan emerged victorious. After slaying Yagdra, she absorbed his essence. Amon is the primary antagonist of the "" expansion and ultimately the main villain of the franchise as a whole.