Gahdok

Gahdok was a Bahrag and the red queen of the Bohrok. She and her sister, Cahdok, controlled the Krana and donned their powers. See Bahrag

Bohrok Swarm
When Teridax prematurely awakened the Bohrok, Gahdok and Cahdok gave the Bohrok their quest to return Mata Nui to the "before time". The Toa and Matoran fought the Bohrok, but little did they know cleaning the island was necessary to awakening Mata Nui. They contolled the swarms from the Mata Nui Bohrok Nest. Gahdok and Cahdok were found when Kopaka followed a Bohrok Va back to the nest. Gahdok and Cahdok battled with the Toa. The Toa wore the Exo-Toa suits, but the armor disabled use of the Toa's elemental powers. The Toa shed their armor and combined their powers to trap the queens in a protodermis seal.

Bohrok-Kal
If the Bahrag were defeated, the Bohrok-Kal would be awakened. The Kal stole the Toa Nuva's Nuva Symbols and inteded to free the Bahrag by inserting them on the Nuva Cube. The Bohrok-Kal were defeated, and the Bahrag remained in their cage.

Freedom
Axonn gave the Toa Nuva a mission to free the Bahrag. The Toa traveled back to the nest and combined their powers. Thus, the Bahrag commanded the Bohrok to "clean up" Mata Nui.

Trivia

 * Cahdok was the blue queen and Gahdok was the red one.
 * The Bahrag were female.
 * The Matoran would have considered the Bahrag to be Rahi, even though they were not.