Pandora is the fortune telling doll owned by Aki. Hence the the name of the shop 'Pandora's Fortunes'.
Kat and most of the other characters assume that Pandora is just a ventriloquist dummy, despite evidence leading it to actually be equipped with mechanical elements that enable it to talk on its own, since Alias was able to hack into it to talk to Chaz using a mechanical voice, and it "breaks down" at the end of Gravity Rush 2, repeating a generic phrase about Raven's "lucky spot" that embarrasses Aki.
However, this alone does not explain why its predictions are always laser accurate. As one of the concept art pieces in the gallery of Gravity Rush Remastered shows a Nevi crawling out of Pandora, this could mean that Pandora is a Nevi controlled robot, similar to the Sea Anemone, and this is the reason it appears to have a mind of its own and supernatural powers. Following the events of Gravity Rush 2, the Nevi inside could have left or disappeared, leading it to revert to its original form as a basic mechanical doll.
In terms of the doll's design, Pandora appears to be based off of a toddler, as evidenced by the red frock and bonnet, small build, and lack of hair on its head. The doll also has yellow eyes with two large cracks on the outer edges. These cracks are far larger and more widespread after Pandora's Fortunes is damaged by a bomb loaded with fireworks.
Pandora also features strange markings running down the middle of her head.
It is hard to fathom what her personality is, as she is just a mechanical doll after all. She appears to be somewhat sentient, though she could also be a prop in Aki's ventriloquist act (if Kat's dour look when Pandora is introduced is anything to go by), but this a just a theory. Even if this is true, the act isn't very convincing.