Jormungand Brood

The Jormungand Brood was one of the major Broods of the Zerg Swarm. It was one of the most heavy-handed Zerg attack forces. Typically called on to follow the fast preemptive strikes of the Garm Brood, the Jormungand Brood relied on its massive numbers and brute force to overcome any foes. It excelled at ground-based combat.

History
The Jormungand Brood may have first risen to prominence during the invasion of Tarsonis. Purple-colored Zerg were used as an attack force on its space platforms. When the Protoss arrived in order to attack it, the cluster was defended by the Sons of Korhal under Sarah Kerrigan. After the Protoss were destroyed, a massive swarm of Zerg warriors overran Kerrigan's base camp and destroyed its defenders, abducting Kerrigan herself. Kerrigan was put in a chrysalis during a long process of being infested, and a new Brood was formed to protect the chrysalis as it matured.

Controversy
There has been some controversy over the actual identity of the brood the player controls in StarCraft Episode II.

The player's Cerebrate controlled a group of Zerg which are purple in color throughout the entire campaign, yet the player had the role of a newly born Cerebrate, not Araq. It could be assumed that the player was part of a brand new, unidentified brood, but the issue is further compounded during the invasion of Aiur, when the narration specifically details that Kerrigan and her brood stayed behind on Char to hunt the Protoss, while the player continued to Aiur, still controlling purple Zerg.

Trivia
The Jormungand Brood is named after Jörmungandr, a giant serpent in Norse mythology that is so large that it circles the world and bites its own tail. It is killed by Thor, who will fall dead after nine steps from Jörmungandr's poison.