Marilyn has black, wispy hair. She wears a white dress with a dark blue button in the middle, and one on the bottom on top of a matching strip of ribbon winding round. Underneath she wears red leggings and purple shoes on her feet. Around her head she wears a bandana which sits above her eyes.
As a member of the Black Ravens, Marilyn disseminates information while managing her parents' stall.
Her easygoing nature combined with a shrewd business sense makes her a trustworthy addition to the gang.
Marilyn is seen managing her parents' stall for most of the game. When Professor Layton, Luke, and Emmy ask her about the black market, she claims to not know anything about it, but secretly informs Crow about their interest, as she is a Black Raven.
When Descole's machine begins attacking Misthallery, she is one of the Ravens who helps find parts and build Layton's catapult in an attempt to destroy the machine.
In the post-credits cutscene, she is seen beside the other Ravens with Arianna, now being a friend of hers.