Brian the Consultant is a criminal consultant who appears in the episode The Consultant and later in Vitamin Sucker. In The Consultant, he helps Dr. Kamikazi be a better villain and catch Robotboy, and as a result Kamikazi fires Constantine. Brian tended to praise Kamikazi, until he betrayed him. As a result, Brian came to Kaziland with the dragon clones to revenge Kamikazi and tell him all his praise was a lie, but then, Constantine shows up to help his boss but fails, and then Robotboy Superactivates, rescues Constantine and defeats the dragons. In Vitamin Sucker, he helps Klaus Von Affenkugel by creating the Vitamonger, that can suck all vitamins and shoot them at Affenkugel to make him stronger. Because of that, Affenkugel fires Ludwig and goes to revenge those who bullied him. But when Affenkugel starts to be smelly, he thinks Brian made him a monster and goes to revenge him. When Robotboy comes to defeat Affenkugel, after he is reverted to is original size, he begs Robotboy to defeat Brian, thus betraying him. Then Brian and his people use the Vitamonger on themselves, and almost defeat Robotboy, until Ludwig and Gus show up. While Gus gets defeated by Brian's people, Ludwig takes Affenkugel to the Vitamonger, and he shoots Brian and his people, inflating them even more until they explode.
- His name is only said several times by Dr. Kamikazi in The Consultant.
- Despite he said he doesn't want to be a consultant anymore in The Consultant, he stays a consultant in Vitamin Sucker.
- In Vitamin Sucker, his clothing's color scheme has been changed. His tie, which was originally purple, became black, and his clothing, which was originally blue, is now a shade of gray.
- He has a cameo in the episode Zap! You're Old. He is seen on a advertising poster. On the poster he is already wearing his black tie and grey suit, despite he never was seen in season three.