Bohrok Nuhvok
The Bohrok are driven by one purpose, to cleanse Mata Nui, restoring it to its former state as a completely barren wasteland. The Bohrok are controlled by the Krana, an intelligent organism, which they cannot function without.
The Nuhvok are the tunnelers of the Bohrok, using the power of their shields to blow up rock and blast passages through the earth. They even have the power to bring down a mountain! Although their reactions are slow, they are dangerously fierce when cornered. When their krana is removed, they can be put to work rebuilding what they have destroyed.
After the defeat and imprisonment of the Bahrag, the Bohrok had their krana removed and were reprogrammed by the Matoran, to aid in rebuilding the Matoran villages.