Marlette is the science child of a Sans and Toriel. Inheriting her parents’s sense of humor and magic, she’s a kind-hearted monster with a slight temper. Her family, while very nice and fun on the outside, is a little bit of a mess. Her strained relationship with her father leaves her frustrated, and outside of her family she doesn’t really have many friends— besides the long lasting friendship she's earned with Poppy.

In the race track, however,it's different. It's an exciting prospect for her. If mildly scary. Voice wise, she's picked up the posh tone of Toriel, with some of Sans's slang. She doesn't speak with contractions.