Dean Collins is a calm, collected, reserved person. He likes order, but not as much as his parents, just enough to organize what he needs. He's very proud of his role as a teacher and of his subject, being very happy to talk about history if asked, a trait the Will, Hay Lin and Orube used to their advantage while searching for information on Heatherfield's past. Dean is also very devoted to those he loves and tries his best to make them happy. He appears to be quite shy and very humble, having hidden from everyone he was a talented and successful singer in his youth; occasionally, he shows some self irony, having once described himself to Will as an "ordinary, boring history teacher" with a smile.
Dean is the son of Simon Trevor Collins, an ex fashion model, and Patricia Bloom, a retired soldier. Despite loving them, he has a slightly complicated relationship with them, due to his laid back nature clashing with their ordered and disciplined lifestyle.
Life as a musician
Dean was the lead singer of a famous band called Greensuit. While singing for the band, he used a stagename, "Cole Dennis". The group released several records before splitting up.
The Guardians thought Mr. Collins was the beast from Meridian, and attacked him. However, he turned out to be human. Will said "I can't believe we zapped our history teacher!" They tried to drag him home in a wheelbarrow, but decided to transform and fly when a police car almost found them. They dropped him into Martin's swimming pool to which Caleb smugly commented "Great. Now his glued on face will fall off faster." They returned him home and covered him in crickets and released his lizard, so that he would think that it ate his shirt while he was dreaming.
Will found out that Mr. Collins and her mother were dating, which made her very upset. She stayed upset about this until she saw Mr. Collins save her mother's life while in her Guardian form. She forgave him and invited him over for dinner.
- Mr. Collins' name is actually a pun. A "Dean" is a person with authority in a specific academic field, or an area of concern, or both. So, Professor Collins would be the Dean of History.
- In the Arc 5: The Book of Elements, it is shown that he likes poetry, as he helped Will figure out that the riddle was an excerpt from a poem "The Enchantresses" by a Heatherfield poet named Thomas Lowitt.
- In the planned season 3, Dean and Susan were planned to be engaged. Susan along with the other Guardian's parents were also planned to eventually find out that the girls were Guardians.