Walter is a pompous young boy and is sometimes the victim to Dennis's pranks. He

What do you want?

is intellectual and does not bother himself of what Dennis and his friends are doing. He seems to enjoy gardening and playing classical music.

Every good hero needs his nemesis - a rival who stands for everything they can't bear, and in Dennis's case that means Walter! Where Dennis is wild, Walter is well-behaved, where Dennis is rude, Walter is terribly polite, and where Dennis is too cool for school, Walter is a snobby, sneaky spoilsport, who prefers quiet studying and difficult homework to rough stuff like fun and games and nasty loud laughter.

He also likes to make trouble for both The Hub Squad and the Animal Mechanicals,which gets on Komodo's nerves a lot. However, he probably had a change of heart that he became a supportive ally to them and sometimes helps them on their missions or mysteries in Season 5, Season 6, and Season 7.