Krana Xa-Kal were the most important type of the eight types of Krana-Kal.[1, 2] They gave their Bohrok-Kal the power to free the Bahrag from their prison in conjunction with the activation of the Nuva cube. Their touch would awaken the Bohrok queens. Their power was unlock.
The Xa-Kal was the most important of the krana-kal. To accomplish their mission, the Bohrok-Kal had to bring a krana xa-kal into actual physical contact with one of the Bahrag.
Both the Nuva symbols and the Krana Xa-Kal were needed to free the Bahrag. The symbols undid the lock, and the Krana Xa-Kal re-energized the Bahrag. Only one Krana Xa-Kal needed to touch the Bahrag. The Bahrag's energies had faded somewhat during their imprisonment.