Ruth is the sort of person who wants to try everything at least once. She can be a little bit reckless and has a wicked sense of humor that can come at the expense of others, although rarely maliciously. That's not to say that the Aquila never does things maliciously; as her younger sisters are well aware, Ruth is in possession of a particularly fiery temper and is good at holding grudges. Despite appearances, Ruth is more of an introvert than an extrovert and it's not unusual to find her in the library or curled up with a book in the common room. Even as an introvert, Ruth often inserts herself into conversations where she doesn't belong and is known to boss other people around without blinking (or thinking of how much older than her they might be).
Although Ruth comes across as a kind of rough-and-tumble tomboy, she actually prefers wearing dresses to jeans - although always with a pair of shorts or leggings underneath, just in case. Her shoes are always sensible and she never wears any jewelry. Her brown hair comes to a few inches below her shoulders when it's not tied back in one long braid (her mother prefers her to wear pigtail braids, but Ruth puts her foot down). She does not wear glasses, although her eyesight isn't perfect; her eyes are brown.
All of her life, Ruth has lived in Maryland, in a small, close-knit community of wizards who also practice Reconstructionist Judaism. She is the oldest child in her family and is closest with her youngest sister. She, in fact, only has sisters - much to the dismay of her father, who is a little bit of a recovering traditionalist. There is a PK-5 school maintained by her community that she attended until she was accepted to RMI, so Ruth came to school already understanding some of the basics of magic. The Fischers are upper middle-class and Ruth has always been financially comfortable, although her parents don't spoil their children.
In general, Ruth will say yes to anything that sounds like it might be remotely interesting - often before thinking.
Because magic and religion have been so thoroughly incorporated in Ruth's life, the idea of secular wizardry is actually a little bit overwhelming. She has never been friends with a Muggle or Muggleborn and while not strictly prejudiced against them, does not really understand their way of life. Ruth does her best to be open-minded, but is not often aware of her prejudices and is inclined to talk before thinking. It wasn't a problem at her elementary school, but upon coming to RMI, Ruth has realized that she's kind of a compulsive joiner.