Although there is very little known about the different Broods that comprise the Zerg Swarms, some Terran scientists have attempted to document and classify a few of the larger Broods that have ransacked their colonies. It seems clear that each distinct Brood stems from a unique Cerebrate that carries out the will of the Overmind [...]. Each Cerebrate is empowered to build its own Brood to accomplish its specified goals. Although the Broods are difficult to distinguish from one another, Terran scouts have witnessed that they vary in functionality and purpose. It has been noted that certain Broods work with each other in unison, as if they were operating as cohesive detachments of a larger, tactical force. Terran explorers have named each discernable Brood with names of ancient beasts from old Earth mythologies. The estimations of the sizes are from the Confederacy [...] era.
THE COMMAND WING
Tiamat
Cerebrat: Daggoth [...]
Estimated size : 6 500 000 (all strains)
Primary directive : Command Fleet
Brood colour : Red
Tiamat is the largest and most powerful Brood within the extended Swarm. It is speculated that the Overmind [...] itself is protected deep within the safety of this living fleet. The most advanced Overlords [...] and Queens [...] define the rigid infrastructure of Tiamat and help to drive the lesser Broods to total domination over their enemies. Tiamat excels at tactical space combat and only dispatches its ravenous surface attackers under the most dire of circumstances.
Fenris
Cerebrat: Nargil [...]
Estimated size : 5 500 (various strains)
Primary directive : Hunter swarm
Brood colour : Green
The Fenris Brood is known for its superior tracking abilities and is often called upon to hunt down escaped breeders and wayward enemies of the Swarm across wild terrain or through the endless void of space. Although the numbers of this Brood are few, it carries out its pursuit with merciless precision and cunning. Their primary role, however, is to find new races and genetic strains that will benefit the swarm through absorption. Once an acceptable race is found, the Fenris Brood will hound it until it has been either assimilated by the Overmind [...] or eradicated completely.
Baelrog
Cerebrat: Gorn [...]
Estimated size : 6 000
Primary directive : Terror Squad
Brood colour : White
The Baelrog Brood consists of the most fearsome of all Zerg warriors. Ravenous and bloodthirsty to the extreme, the Baelrog Brood is often called upon to sow terror and confusion amongst enemy ranks. Resorting to atrocious acts of cannibalism and indiscriminate slaughter, Baelrog typically causes enemy warriors to flee for their lives or turn upon their own kind in order to find some desperate means of escape from the horrendous Zerg onslaught.
PRIMARY STRIKEFORCE
Garm
Cerebrat: Zasz [...]
Estimated size : 10 000 (various strains)
Primary directive : Primary Assault Force
Brood colour : Orange
Named after the fierce hellhound of Norse myth, Garm strikes with alarming speed and ferocity. The minions of this Brood excel at hit and run raids that weaken their enemyís defensive formations. Zasz, the cunning Cerebrate of this Brood, delights in preemptive attacks, relying chiefly upon surprise to throw enemy forces into total chaos.
Jormungand
Cerebrat: Arag [...]
Estimated size : 3 000 000 (all strains)
Primary directive : Primary Support Force
Brood colour : Purple
The Jormungand Brood is one of the most heavy-handed of the Zerg attack forces. Typically called upon to follow Garmís preemptive strikes, Jormungand Brood pacifies all other resistance to the Swarm. Jormungand relies on strength of numbers and brute force to overcome any foe and excels at ground-based combat and direct unit-to-unit warfare.
Surtur
Cerebrat: Kagg [...]
Estimated size : 2 600 000
Primary directive : Heavy Support Force
Brood colour : Blue
Should the Jormungand Brood fail to achieve total victory over an enemy force, the Surtur Brood is released into the combat zone. Named after the fiery Titan of destruction from Norse mythology, the Surtur Brood is let loose upon any remaining enemy warriors. This Brood is so completely destructive when unleashed it is kept restrained within the recesses of the Zerg fleet and is only called upon under the most extreme circumstances. The Surtur Brood has been known to eradicate friendly Zerg troops as well as enemies in its furious rampages.
OTHER
Grendel
Cerebrat: Segal [...]
Estimated size : 10 000 000 (various strains)
Primary directive : Incubator
Brood colour : Brown
The largest brood named after beast in the medieval english literature, who is "father of all evil", has a clear purpose - breed. It is situated out of lines as supply and breeding force. The brood consist mainly of drones [...] and hatchery complex. It has warriors only for it´s own protection and the most of the hatched Zerg go under the control of other broods. Members of this brood have been observed with stronger carapaces, than usual Zerg have.
Leviathan
Cerebrat: Targ [...]
Estimated size : 50 000 (various strains)
Primary directive : Subaquatic strikeforce
Brood colour : Yellow
The name of the brood is derived from the biblical underwater dragon, implicating it´s designation. Under common circumstances the numbers of this brood are very low, but should the underwater battle occur, Overlords [...] and Drones [...] are able to settle underwater immediately and produce large amount of subaquatic warriors. Drones and overlords of this brood are much more effective while moving underwater, than Zergs from other broods, but they are slower on the ground.