Kurahk

Kurahk was the Master of Anger. Though he was fast and strong enough to down any foe, Kurahk perfered to turn his opponents against each other. His Staff of Anger could fire rings of anger, causing the target to be consumed by rage. Even the Toa Nuva were not immune to its power, which magnified any difference of opinion into an all-out physical conflict.

Kurahk was released by Teridax with Turahk and Vorahk. During one battle in Onu-Koro, Kurahk used it's powers on Tahu who became really angry. Kurahk's anger actually increases its powers.