William here is actually the latest of the fan-made characters to be introduced to the cast as a result of the Peter & Company Kickstarter. The highest reward tier for the campaign allowed each contributor to create a character to become a permanent member of the cast.
William's creator is one of the most dedicated readers of the comic I've met so far, like a walking encyclopedia of P&C knowledge. It was a blast working with him to come up with William's final design and place within the comic.
