Mandy is one of the three title characters from The Grim Adventures of Billy & Mandy and is possibly the most feared person from the series. She has a very cold personality and is often seen as scary, even by her own family. In only three of the eighty episodes of the series did Mandy ever crack a smile. She has a tendency to boss Billy and especially Grim around all the time. Strangely, while in the show Mandy has no nose (and was sometimes made fun of because of it), in FusionFall she does, though her Nano remains nasally deprived.
In FusionFall, she can be found at Devil's Bluff plotting to raise her own troops after hearing about Mojo Jojo and his plans for creating an alien army.