He is incredibly timid and never gets around to teaching due to his fear of Vendetta's reactions to his lessons. He speaks in a nervous, disjointed monotone and is afraid of the fanged red bird fiend that is constantly glaring at him. Mr. Milk fantasizes about being a Swiss banker and having a relationship with Ms. Minty.
Fiendish Trivia
Mr. Milk drinks nonfat milk.
He is the only known character to ever wear a wig.
He is also the only character ever to have a hairpiece that doesn't match his body color.
He is a little similar to Mr. Garrison from the longest running adult-animated series, South Park. Creator, Amy Winfrey and screenwriter, Peter Merryman were once part of the South Park crew.
Mr. Milk wishes to be a Swiss banker. Considering that he dreams to live in Switzerland and stores a bank vault with cheese (Swiss is a type of cheese), this is likely a stealth pun.
Like Charlotte; he is a good singer, most likely in a tenor note. Considering that his voice actor, Peter Merryman, also sings.