Original: The character , created by Michael Dante DiMartino and Bryan Konietzko , was voiced by Mako in the first and second seasons , but after Mako 's death of esophageal cancer , Iroh was voiced by Greg Baldwin in the third season .
Simplified: The character and series were created by Michael Dante DiMartino and Bryan Konietzko . Iroh is voiced by Mako in seasons 1 and 2 , Greg Baldwin onwards .