Diane was depicted as a young and beautiful woman with a cheerful face. She had light beige skin and sunny blonde hair below her shoulders. In Sal's dream, she is dressed in a hospital gown. In another one of Sal's dreams, she had a short chocolate-colored dress, due to her son's limited memory of her when he was young. In both dreams she wears dark brown ballet flats. She wears a wedding ring on her left hand.
Diane loved her husband greatly, but she loved Sal more than herself. She is willing to indulge Sal's adventurous side when she allows him to visit a dog in the park, and even saves him, despite the action later costing her life.
Diane's life is mostly a mystery. However, it is heavily implied that she was a good wife to Henry and a loving mother to Sal. Their normal life was changed the day the Fisher family went on a picnic and the youngest wanted to pet a stray dog.
Her death affected both Henry and Sal greatly, driving Henry into sadness and insomnia. They later moved to their new home - Room #402 in Addison's apartment.
It is shown that Henry still holds Diane in his heart by setting the password of his computer to her name in the form of numbers (491145) and keeping one remaining letter from her underneath his bed, which Sal thought he threw away.
It was after Diane's death, according to Sal it all went wrong, she died either trying to save him from a rabid dog, or at the hands of a man as Sal affirms in The Wretched.
If she was actually killed by a man, the man responsible for her murder is likely “Dogma” the leader of the Devourers of God, who wears a dog mask.
- Diane is the youngest woman in the game.
- Diane's role appears with roles of many mothers who have died and are described in fairy tales. As an example Sal "mentions" her as the kindest and most gentle woman in the world.
- She was a loving mother and wife, as far as we can judge by an inscription on a gravestone.
- According to Sally, his dad has thrown away all of their joint photos.
- However, in The Bologna Incident, one of her photo was find under Henry's bed in Room #402. Despite the detail of the photo, the player only know the number on it.
- There are dates of birth and death, mentioned on her gravestone, it says 1948-1984. At the time of death Diane was at age 36, it means that Sal was 3.
- In the beginning of Strange Neighbors, her corpse was shown with strange wound on her scalp, probably it was a bite.
- Probably her death was caused by the attack of the dog that carried rabies.
- Another possibility is that she was killed by the leader of the cultist group, Dogma, who wears a dog mask that closely resembles the dog silhouette we see when younger Sal is traversing through the forest.