Frontier Brains (Japanese: フロンティアブレーンFrontier Brain) are the owner of a facility on a Battle Frontier and are of the highest rank, much like a Gym Leader is to a Gym. Similar to a Gym Leader's Badge, Frontier Brains will hand out an item to a Trainer that proves their skill and is a sign that they have been beaten by that Trainer. Hoenn region Frontier Brains will give out Symbols, while Sinnoh region Frontier Brains will give out Prints.
In the anime, Ash defeated them all. When Scott asked Ash if he wanted to become a member of Frontier Brain, he declined the offer.