Varrick

Iknik Blackstone Varrick is a major character in The Legend of Korra, serving as the secondary antagonist of Book 2 and an anti-hero in Books 3 and 4. Initially introduced as a helpful ally to Team Avatar, Varrick was revealed to have orchestrated the Water Nation Civil War and instigated multiple terrorist attacks in Republic City in order to make a profit from those conflicts. He is also the husband of Zhu Li Moon. 
While Varrick is initially shown as selfish, ruthless and somewhat insane, he became a better person as the series went on, and eventually, the good he did outweighs the bad and he became a major ally of Team Avatar.   
He was voiced by John Michael Higgins, who also played Drex in Super Buddies, Warren Stone in Rise of the Teenage Mutant Ninja Turtles, and Cad Spinner in Planes: Fire and Rescue.