Gerard Mystery is the father of Martin Mystery and step-father of Diana Lombard when his son and stepdaughter were very young. He is a very strict man, but he is also caring towards Martin and Diana. He isn't into the paranormal and supernatural since he showed up in the 3rd season of Martin Mystery.
Gerard is very similar to Diana they are both serious, smart, Brave, rational, Obsessive, They both get annoyed by martin's Childish behavior.
Gerald bears some resemblance to his son Martin.
Gerard loves Martin. But Gerard get's annoyed by martin childish behavior. And the fact that Martin never study's or work hard in school. Like Diana Gerard hates when Martin pulls pranks on people.
Gerard Loves Diana very much and they have a great relationship with each other. Gerard seems more fond of Diana then Martin. Because Diana is a lot more smarter then Martin and Diana does not pull pranks on people like matin does. And Gerard loves how hard Diana study's and work hard in school.
- He taught his son how to twist the lynx' ears when they tried to bite Martin.
- He eventually learns about Martin and Diana being Center agents alongside with finding about Java, Billy and M.O.M in the episode "Wrath of the Torrington Worm".