Mary Mongoose is the daughter of Ash and Mina Mongoose. Mary had grown up with friends Tark the Echidna and Alex the Hedgehog who she had a crush on like her mother once had on his father Sonic the Hedgehog. Mary wanted to be a Freedom Fighter and join Future Team Fighters and travel the world but her mother and father worried that she would be put in danger but it was reveled she had super-speed that far surpassed her mother's and was around Sonic's level and Sonic promised her parents that he would teach her how to use her powers and defend her self so she could join when she turned 15.
Mary is a polite and outgoing girl, who is often frustrated by people being cowards. It is noticeable that she is a lot braver than her mother, Mina, and a lot louder then her at that age.
Mary also seems to have a budding romantic interest in Alex at first site. Over time a relationship with Alex is starting to develop, and Alex eventually began to think of her as girlfriend material. The two engage in flirting, and even an occasional gesture of affection in public. After a few missions Alex asked Mary out to dinner, which she accepted.
Mary has the gift of super speed, it is even in comparison to Sonic, she is considered a formidable combatant. In addition to her speed she's a skilled fighter who specialises in kicks, she is both a swift and agile fighter due to her speed and training from Rouge the Bat. But she also has talents that lie outside of battle—namely, in singing.