The Brains are a species of parasitic beings from an unknown source.
<spoiler>After being given the task to destroy Hero Factory, the Brains left their home planet floating in space, but a solar storm separated one swarm from the rest.
This swarm found the Valiant floating in uninhabited space. The Brain swarm leader took over the body of the ship's commander Kirch, and the entire crew was soon infected. Afterwards, the Brains placed the Valiant in a collision course with Hero Factory with plans to destroy it.
Hero Preston Stormer started a conversation with the Valiant's captain, his friend Aquax, who, being under control of the Brains, claimed that the ship had an engine trouble. Stormer, suspicious of his friend, boarded the ship along with his fellow Heroes Natalie Breez and Rocka. Inside, they were attacked by Aquax and the rest of the crew, with Kirch taking Rocka as a hostage. Thankfully, the Heroes were unintentionally saved by Xera, the ship's medical technician, but only because Aquax was disobeying Kirch's orders. Meanwhile, several Drop Ships led by Nathan Evo approached the Valiant with plans to avoid the ship's collision with Hero Factory, but Kirch activated the Valiant's firing system to stop them.
However, after the arrival of Dunkan Bulk and William Furno, along with Stormer and Breez defeating an array of crewbots dominated by the Brains, Kirch was forced to give up Rocka, as Stormer changed the Valiant's course to the sun. Kirch then made the course permanent and attempted to leave the ship due to the danger of being burned alive, but as the temperature outside the ship was already too high, Kirch and his team was vaporized. Afterwards, by using the explosive cargo inside the ship, Stormer changed the course of the Valiant away from the sun, ending the crisis inside the vessel.</spoiler>
Abilities and Traits
<spoiler>The Brains can survive in space, and have a single purpose: to destroy Hero Factory. They can attack by latching onto a host's head and taking control of them, absorbing their knowledge but not emotions. The Brains have leaders of groups called swarm leaders, these leaders' orders are generally followed, but not by all Brains, as evidenced by the one controlling Aquax. The exact origin of the Brains is unknown, but Aquax theorized that they do have a home planet and plan to begin an invasion of the galaxy.</spoiler>
A single Brain was included in each Pyrox, Scarox, Ogrum and Bruizer set, released in the winter of 2013 as part of the first wave in Hero Factory's Brain Attack line. The Brains were made of rubber, with a plastic piece to connect it to the recipient's head, and they were colored yellow, dark green, light green and orange, respectively.