Kolrahk

Kolrahk is the makuta of Cortaka Nui. He owns a huge fortress underground which none of the matoran of Cortaka Nui know about. Kolrahk was a makuta who was once benevolent to the matoran race, giving them tools, supplies to build cites, and shelter. However, a dark makuta spirit known as Voltrahk possesed him. Now, evil he tortured the matoran. Kolrahk later decided to worry about bigger things than his matoran population, so he made robots to worry about them for him.The Kolrahk Robots are enforcers  of justice just like the vahki. They pretend to protect while the secretly kill. Kolrahk had no time to worry about them as in his eyes there was much to do for Teridax's plan.