Steinfeld

Steinfield Billiam is a DunderButt living near Jason Gastrow's neighborhood. In the past Steinfeld had worked as a voice actor for children toys, creating evil toys that attacked their owner. Dunkey owned a toy under Steinfeld's influence and it stabbed him in the neck.
Several years later Steinfeld had fallen on hard times and was living homeless. 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 some lines for his video but Steinfeld became nervous by his aggressive manner and decided to flee. Dunkey tracked him down and abducted him to make him record more lines. 
Eventually Dunk went to visit his uncle King Phil in Bel Air and left Steinfeld with some cheese Doritos. Steinfeld used his powers to escape from the dungeon and visit King Phil as he too wished to become his heir. Dunkey was outraged at Steinfeld trying to usurp him so put him in the dungeon of King Phil's manor. Steinfeld escaped by cutting his leg off and replacing it with a mecha leg. Dunkey managed to become King Phil's heir and so King Phil tasked him with running a bakery with Bill Brick. Steinfeld had a diabolical plan to invade Hawaii and Dunkey was too busy to stop him. Eventually they had a showdown in Hawaii but Steinfeld blew up the place with a nuke, sending Dunkey to the moon. 
Steinfeld 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. 
Dunkey and Steinfeld next meet when Dunkey is trying to find who created the evil GI Joe toys. He tracks down a lead to Dolphin Flipper Studios and realises it was Steinfeld the whole time. They fight and Dunkey blows him up in a helicopter explosion, thinking he is dead. 
Dunkey went to jail several times for assulting a manager at McDonalds and then comes face to face with Steinfield once again. Then they have a final showdown in outer space where Dunkey and John Madden use Madden Missiles and Bret Fauvre Cannon. Unfortunately they are not strong enough and Steinfeld is about to kill Dunkey. Then Bill Brick comes to build a wall around Steinfield and Dunkey uses his Dunkey Blast to finally defeat Steinfeld. 
Steinfield is also known to be a singer for the band known as the rough riders, and an employee YES PIZZA ROLLS