From Homestar Runner Wiki
 Welcome to me!
Good day, my loyal subjects! I am DarthWill3, the Dark Lord of this website! Please remain standing whilst I go route for the KOT and try to get www.homestarrunner.com to accept some of my artistic email ideas!
 My theories
Theory 1: I believe I have figured out who Biscuitdoughhandsman really is: Coach Z's own dad, though Coach Z is too ashamed to admit it. He's probably been working for the King of Town as his personal chef, while Coach Z was teaching the others when they were kids, such as Lil' Strong Bad. Then, while fixing up some biscuits for the KOT, he didn't know the two radioactive gems Homestar sneaked in the flour before entering them into the science fair. Then, while placing the dough in the heating oven... BOOM! Biscuitdoughhandsman is born and out to take revenge on the KOT after believing this was the thanks he got for serving him. That would pretty much explain for Coach Z for thinking his dad had stolen the KOT's crown.
The articles I made so far: