It was speculated that the Overmind itself was protected deep within the safety of this living fleet. The most advanced overlords and queens defined the rigid infrastructure of Tiamat and helped to drive the lesser broods to total domination over their enemies.
The Tiamat was specialized in tactical space combat and rarely fielded any ground creatures. It only dispatched its ravenous surface attackers under the most dire of circumstances. It was infamous for breeding the most specialized and advanced zerg, such as the Hunter Killer hydralisk strain.
The Tiamat Brood protected Char's planetary orbit during the Great War. When General Edmund Duke of the Terran Dominion led attack forces to Char, the Tiamat Brood attacked his forces as they fell back.
During the invasion of Aiur, elements of the Tiamat Brood were at the forefront of the attack, along with the Grendel Brood and the Baelrog Brood. They were the broods that invaded the provinces of Antioch and Scion, destroying the protoss defenders. Parts of the brood also remained on Char hunting the protoss who remained there.
The brood took part in the ineffective defense of the Overmind, and remained active throughout the Brood War. By the Second Great War, elements of the Tiamat Brood had become feral, though had some of the last lurker dens.
The Tiamat Brood is named after Tiamat, the dragon from whose slain body the universe was made in Babylonian mythology.