Lady Dahlia was programmed to be bossy and concerned most of the time about herself and her welfare. Sometimes she sees her erased persona in her dreams, and remembers Lady Violet's memories, but dismisses it as just being dreams. Poor Matthew is the person who takes Lady Dahlia's rage most of the time. But she has a hidden sweetness, which shows in Flora's decision to leave St. Mystere with Professor Layton and Luke. She also adores her cat Claudia, calling him her "baby" and feeling upset when he runs away (though she treats him like a female, much like the other characters).
Lady Dahlia is a robot created by Bruno to behave exactly like the Baron's previous wife, Lady Violet. Her original purpose was to be a gift for Flora. The baron, however, was very upset at how she was identical to Violet, so he ordered Bruno to wipe its personality and memory clean, and to create a new woman, Lady Dahlia. When she met Flora for the first time, Flora was terrified by the sudden change of personality. It was also noted in the baron's journal that he felt terrible for forcing the change on Flora.
In Curious Village, Lady Dahlia wrote a letter to Layton asking for his help is solving the puzzle of her late husband's will. When she and Layton first meet, as they go to shake hands, a loud booming noise shakes the walls of Reinhold Manor and scares away her cat, Claudia. She sends Layton and Luke off to find her.
When they arrive back, they find out about Simon's death, in which Lady Dahlia is determined to prove her innocence in. At the accusation of Layton being Simon's murderer, she witnesses Layton prove that Inspector Chelmey is in fact Don Paolo.
At the end of the game, when Flora decides to leave St. Mystere, Lady Dahlia sends her off happily, as she is willing to support Flora's decision.