Well, look who's back! Hooray, human-shaped Madison made it into advertising. (She wouldn't normally be in human-shaped form, by the way.
From this point on, Madison Berry is simply Madison Berry, and her character is no longer associated with any real human beings.
I'll draw her from time to time, but like Mr. JB stated at the end of Episode 12, he'd never visit the city in an episode again. Which means she'll no longer be on the show, mainly because:
1) She wouldn't have a voice, and
2) I don't like cartoons to have new protagonists introduced, like what happened with Rugrats after the movie, and I haven't really watched Regular Show since 2011, so I'm not sure what Thomas has done for the show.