Diana is a serious, rational, and obsessive straight-A 16 year old student with nothing in common with her stepbrother. As an agent at The Center, she strives to bring more seriousness into Martin's life, and is Martin's female counterpart during investigations.
Diana's appearance was shown as a slender, 16 year old Caucasian female with light brown hair, with two signature purple hair clips, and dark green eyes. Her main outfit is a long sleeve pink shirt with dark pink sleeves, light blue jeans that stop at her knees and pink and white sneakers with no socks in them. She is usually seen with her small purple shoulder bag.
Diana is at times quite jumpy and squeamish on missions, but shows great courage when called on. Not sharing Martin's love of the paranormal, she often tries to explain something with logic before it becomes apparently paranormal.
Diana has the hardest time keeping her cool and temper with her irresponsible stepbrother, and will generally slap, kick, beat or scream at him quite often with physical abuse. Regardless of Martin's quirky and hyperactive behavior, she loves him like her own real brother.
Diana has a love hate relationship with Martin and slaps, kicks, Beats, and screams at him when he pranks her.
Diana loves her stepfather very much and enjoys spending time with him.
Diana has a great relationship with Java and enjoys spending time with him.
Diana likes Billy a lot and does not want to see anything bad to happen to him.
Diana has a strong like for mom even through Mom yells at her and Martin most of the time.
Diana and Jennie have been best friends for a long time and they enjoy spending time with each other.
Diana has a huge crush on Marvin and wants him to fall in love with her.
Role in the series
She is probably the second or first victim in the episodes including being cocooned by an acid spewing insect queen from Terror from the Sky, and being possessed by a vengeful spirit at a mountain lodge from Haunting of the Blackwater.
- Her physical appearance and personality are similar to another character, Samantha from Totally Spies!.
- In the animated series, Diana is Martin’s stepsister, but is his girlfriend in the comic books.
- As shown in the episode, Night of the Scarecrow, she is not much of a farm girl.
- Diana is the smart one of the group.
- When Martin is transformed by the monster, Diana uses her own skills to save him. In a few episodes, Diana wears Martin's U-Watch and uses it when he loses it while being transformed.