Gelrax

"You can't kill me, foolish Toa. In this world there is always Darkness and Light.  You are the Light, and I am the Darkness." -Gelrax, talking to Jatax in his lair, before the Toa, Krika, and Mutan killed him.

The Evil, Powerful leader of the Brotherhood of Makuta. He has been the leader for over 2000 years. He's killed countless Toa, Rahi, Protectors, and even Makuta. His lair was on the Island of Desei. He killed the Original Toa-Tera, but was killed on Desei by the Toa-Sei. He made Mutan and Samurai, but later killed Samurai.