Bromine

Bromine is an old, wizened wizard who runs the Speed Quest. He employs The Guild in order to rid a nearby settlement of a creature that is stealing out of their bins.

He is the brother of Bismuth.

Trivia:

 * He and Bismuth share a lot of similarities, including that they are both incredibly old and can both transform into vehicles (Bismuth can turn into a jet, and Bromine a truck).
 * He states that he is fine with people calling him Brom, but only his sister, Bismuth, can call him Bro.

Behind The Scenes Trivia:
Johnny revealed that he is Bismuth's brother in the Youtube video of Fast and Furriest.