Bohrok Tahnok
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 Tahnok are the most aggressive and destructive of all the Bohrok swarms! They use their mastery of fire to burn and melt whatever's in their way. Even with their krana removed, Tahnok are hard to tame.
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.