Joaquim Dos Santos is a PortugueseAmerican television director of animated cartoons best known for his directing work on Justice League Unlimited Avatar The Last Airbender and The Legend of Korra He was a storyboard artist for Justice League before being promoted in the shows renamed third season He went on to direct half of the episodes of JLU alongside fellow DCAU director Dan Riba including the final episode Destroyer He joined the staff of Avatar The Last Airbender in the middle of the shows second season as a storyboard artist and began directing episodes in the third season including the last two parts of the fourpart season finale He also directed the miniseries GI Joe Resolute After that project he moved back to Warner Bros Animation where he directed two DC Showcase short films The Spectre accompanying the Justice League Crisis on Two Earths directtovideo movie and Jonah Hex on Batman Under the Red Hood He is now working as an executive producer and coshowrunner on the animated series Voltron Legendary Defender with Lauren Montgomery Some fans have nicknamed him Dr Fight because of his skill at choreographing fight sequences and action set pieces