Cahdok

Cahdok was the blue one of the two Bahrag sisters, a queen of the Bohrok swarms.

History
The Bahrag were created by the Great Beings to lead the Bohrok swarms.

The Bohrok War
When Teridax awakened the Bohrok, the Bahrag were the ones who assigned them the task of "cleansing" Mata Nui (Location). Although the Matoran and Toa tried fighting back, they couldn't stop them for good.

Kopaka discovered the location of the Bahrag's lair after following a Bohrok Va.

Before fighting the Bahrag, the Toa Mata donned powerful machines known as Exo-Toa. During the fight, however, the Exo-Toa's weapons proved to be useless against the Bahrag. The Toa then realized the Exo-Toa kept them from using their elemental powers, and they exited the machines. The Toa then imprisoned the Bahrag in a special Toa Seal known as the Nuva Cube.

Bohrok-Kal
After the defeat of the Bahrag, six special, elite Bohrok, the Bohrok-Kal, were awakened. Their purpose was to awaken the Bahrag, should they be imprisoned. The six Bohrok went to each Wahi and stole the Toa Nuva's Nuva Symbols. However, before they could awaken the Bahrag using the seals, they were defeated by the Toa Nuva, who channeled their powers through the symbols.

Freedom
One of the tasks on the Scroll of Preparations was to "clean" Mata Nui using the Bohrok. The Toa Nuva then went to the Bohrok nest and freed the Bahrag, who unleashed the swarms on Mata Nui.

Powers and Equipment
Cahdok, like her sister, had control over the Elements of Fire, Water, Earth, Stone, Air, and Ice. Additionally, she possessed the powers of Acid, telepathic control over the Krana, and a symbiotic connection to Gahdok.