She is generally calm and quiet, often very thoughtful to the point of not hearing what others are saying. However, she becomes aggressive when she is annoyed too much, is in a bad mood, or feels attacked. She has sudden mood changes (she can go from the wildest joy to crying in a short time and vice versa, up to the phase of total apathy), experiences emotions in an intense and amplified way and is not always able to control herself and often leaves succumb to them; despite this, she seems to have difficulty understanding other people's emotions (alexithymia) and when she sees them expressing something in front of what she says, she asks "Is that a problem?". When needed, she proves to be eager and generous, even if often she doesn't feel reciprocated in this and when it happens she becomes intractable, capricious, victimistic and self-centered in the face of what she thinks seems unfair: but then, when she calms down, she knows how to control herself and face them as it should.

She's also quite curious: she likes to learn new things when she's interested in doing so. She is quite independent, but also introverted and socially inept: when she tries to make friends she does it awkwardly, but when she succeeds she becomes more outgoing. Although young, she demonstrates a strong intelligence and is sometimes even wise. However, she proves insecure and naive in front of unknown people, but also showing a certain curiosity for them and opening up to them when she is sure she trusts them (although this often causes her trouble). She can't tell lies and is sometimes quite direct and misunderstands what is being said to her, because she doesn't get it right away.

She has learned to adapt even to what she doesn't like: for this reason, despite her condition, she doesn't seem to show that she has too particular needs, and if she does, she prefers not to reveal them so as not to be too much of a burden to others.

She was born as a half-blood witch from Maurice, an English pure blood wizard, and Veronica, a Muggle-born Italian woman who works and lives in England. Maurice was working in the Minister of Magic with Arthur Weasley and met her future wife while she was buying some food in their break time. She was looking for a money that she dropped and he helped her finding it. They met again in a park while they were walking with their dogs and started to chat and meet again after the work. They got married after some years and decided to live together in Veronica's house. After two years of marriage, Maurice and Veronica had a daughter and named her Frances; when their dogs died of old age, they decided to adopt a calico cat as a birthday gift for Frances, who named it Piper.

Frances grew up by having a great knowledge of animals, especially marine ones, and to be good at drawing too. She discovered to be a witch thanks to medical exams and her parents enrolled her in the Hogwarts School of Witchcrafy and Wizardry, where she got sorted in Hufflepuff.