Three

Three is the third of his siblings, often assuming different roles in each episode, although he sometimes dresses like the same person. He has many personalities and accents in each episode. He is only seen in two episodes where he acts as himself with no accent. He is voiced by Dwayne Hill. He will be voiced by Dan Castellaneta in the reboot TV series.

Three is voiced by Dwayne Hill in both US and UK versions.

The original book by Maurice Sendak, Three is the only monster who gets an entire page to himself. The line for him is Three comes creeping into town.

Three
Born	Unknown
Sex	Male
Species	Monster
Family	Mom (her real name is not mention), 2 sisters (One and Six) and 4 brothers (Two, Four, Five and Seven)
Friends	Mary and her friends

Appearance

Three is a monster with brown fur all over his body and with a little bit darker hair on his head, dark yellow eyes, and horns on the top of his head. As his normal attire, he wears a long maroon robe with a patch with number three on it and one of his sleeves being shorter than the other. He is mostly seen with his normal clothes in mostly posters and fan art. He has a unique cat like appearance. 

Personality

He is a smart monster when he is taken different roles and shows his siblings about different things depending on who he decides he will be. There is an episode ("High Noon") in which Four was going to throw an egg in the bowl and Three looks excited before his mother stopped Four.

Three often serves as a teacher in the series who often uses his disguises to teach his siblings about different things like the ocean and gravity, thus helping to put an educational spin on the series.  

In "The Adventures of Super Three", it is shown that Three is likely to be afraid of mice.

Three's normal voice can be heard in "Ahoy, Me Monsters" when he opens a letter, the beginning of "All's Quiet on the Monster Front", the story Mom read in "Good Night", and "Are You My Family?" His normal voice also sounds similar to Superman character Jimmy Olsen.