He is

Penny thought that Dean was the biggest omen she would face tonight. However, she immediately realized she was wrong. Overcoming Dean and dealing with him wasn't the end of it. She wasn't completely saved yet. There was still Mildred.

"See? This is what I'm talking about! You snuck out earlier just because you think the kitchen work is beneath you, but look what happened! If that wasn't the First Young Master Dean from the First Branch, this could've turned out much worse."

Penny listlessly tossed the trash bags into the large bin while Mildred continued to sing from behind her, following her like a talking shadow. Penny had enthusiastically volunteered to continue taking out the trash to avoid being nagged by Mildred, but Mildred simply followed her to continue nagging.