|There are spoilers for the LittleBigPlanet series underneath this header. Read at your own risk.|
When Marianne Noisette was captured by the Hollows, Sean Brawn took Sackboy to his spaceship claiming that if he wants to save the world, Sackboy should help him discover where the Hollows put their cargo in Jackpot City. During the end levels of Jackpot City, The Hollows reprogram The Megabrain causing it to attack Sackboy. Sackboy defeats The Megabrain and Sean is late to the party. He is captured by The Hollows as well and put in a crate. He makes a brief appearance in Coaster Valley saying "Sackboy, sombody said yahoo right now". In the end cutscene "The Power Of Laughter", Sean, Mrs Sunshine, Colonel Flounder, Marianne Noisette and The Unbelievable Otis crash through the ceiling. They all meet the Puppeteer and then the Hollows reappear. Sean tells everyone to turn off the lights to catch the "ringleader" but he accidentally grabs Otis causing the everyone to laugh including the Puppeteer who release the old puppets from the Hollows because he laughed.
He appears to be made of metal and doll parts. He has a mustache and a crew cut, a large chin and a pipe made of what appears to be a toothpick and a cork sticking out of his mouth, a metallic body that looks like an engine, a spring attached to a plastic muscled arm, a rod with a hook arm, another spring attached to a peg leg and a blue and white striped leg with a boot.
Sean Brawn considers himself to be a great hero, similar to Avalon Centrifuge. However, unlike Avalon, who's ego is somewhat justified by his inventions, Sean Brawn only ever gets into trouble and messes things up, annoying The MegaBrain to no end.
His surname, Brawn could refer to physical strength. Brawn may also refer to a type of jellied meat, however it is most likely the former.