Steinfield Billiam is a DunderButt living near Jason Gastrow's neighborhood. Dunkey wanted a voice actor for a DunderDota 2 video he was making, and hired Steinfield for $1.20 an hour. Dunkey brought him to his house and wanted him to say the line "Dunderbutt'. After questioning the script, he finally gives in and attempt to say the line. Dunkey is dissapointed by the lack of acting and threatens Steinfield to do a better job, holding a knife to his neck. Through terrified tears, he succeeds and finishes the voice work and leaves with his money. the Next day, Dunkey tries to hire him a second time to continue what he did yesterday, but Steinfield denies ever meeting him, and walked away. 1 week later, Dunkey travels to Chicago to hunt him down, believing he exploited his crime to the hobo community, and runs him over, injuring his legs. Dunkey kidnapped Steinfield and locks him up in his basement, forcing him to do voice work.
A while later, Jason is summoned by King Phil of Bel-Air to become the next fresh prince. He leaves Steinfield home with nothing to eat but a bag of Doritos. Jason forgets to lock the handcuffs to the saw trap and Steinfield manages to escape and follow him to Bel-Air. It's later revealed that Steinfield hired the Best Buy geek squad to build him new robotic legs. Steinfield fails to win the friendship of King Phil when Jason becomes the new fresh prince, then returning to his basement prison. Steinfield escapes once again and joins a terrorist orginization, and then holds the Islands of Hawaii hostage. Steinfield manages to destroy Hawaii with an atomic bomb and later captures a city in Africa. Dunkey manages to save Africa by knocking Steinfield into a Space Hula Hoop, and surrenders, calling a temporary truce to enjoy the pizza party.
Steinfield is also known to be a singer for the band known as the rough riders, and an employee at DolphinFlipper studios. He is also supposed to be a boxing champion, and has a powerful final form revealed in Space Hell Grand Prix known only as Mega Steinfeld according to Dunkey. He can also transform into what looked like an Alien, according to Dunk
The story as told by Dunk can be found here: https://www.youtube.com/watch?v=YXspfbij6S8