Precis F. Neumann, age 16, lives in the eccentric town of Linga with her father. She loves tinkering with machines in a world where hardly any of them exists.
Always cheerful and energetic, Precis decides on a whim to follow Claude and the others in their quest; whether she does this for her instantly developed crush on our male protagonist, because of her technical interest in the Sorcery Globe, or because she saw this event as a good excuse to leave town and go on an adventure is anybody's guess, but I'd say it's a combination of all of them. She doesn't really take an active part in the main story of the game, but she makes sure you won't be able to ignore her, what with her loud dialogues and wealth of Private Actions.
Even though few people could think it possible, Precis dresses even more weirdly than Rena and Celine combined: what stands out the most is her robotic equipment, with a half exoskeleton filled to the brim with accessories (including, but not limited to a huge hammer), clown shoes or something (presumably with shock absorbers), and a Sony Dual Shock controller to control all her electronic stuff. She wears some kind of work suit, and you can see her tights ripped on her knee, a sign of her clumsyness. You can't see it in the artwork, but she also carries Bobot, everyone's favourite radio-controlled car - as Claude loved to refer to it - with her anywhere she goes; or, rather, she's busy chasing after it most of the time, which suggests us it's either seriously broken or it's got a will of its own. Her game sprite widely differs from this drawing: the colours are all different and, instead of the exoskeleton, she carries a backpack.
Precis's interest in Claude probably generates, aside from physical attraction, from the fact that he showed some curiosity towards the neat stuff she works on, instead of staying away from her and from her machines like everyone on Expel does. Of course, for an Earthling machines like that are nothing special, and for Claude (who's decently knowledgeable in science subjects) it's normal to see someone working on them; however, a machine geek is still a geek, and Precis geekery, coupled with her hyperactivity, makes sure her love for Claude is one-sided (at least by default, since the player can change that).