User blog comment:PerhapsTheOtherOne/Synthetics In RWBY and Beyond: What's that all about?/@comment-25405817-20150601025235/@comment-25555436-20150601031440

Alternate idea (somewhat): Penny was human, but she died. As such, her father made a robot, based on his daughter, with an exact replica of her mind, her personality, and the rest, though problems with the space in memory caused some complications with her memories.

OR "Geppetto" was hired by the Atlesian government because of his known skills with machines, to make an effective anti-Grimm combat robot on-par with a Hunter and capable of using Aura (though I have some questions about that). But Geppetto's daughter had died not long before, and he was obsessed with it, couldn't let it go, and before he knew it the combat robot ended up looking identical to his dead daughter, the AI even had the same personality, with 1 major difference: the AI and Geppetto both knew she wasn't "a real girl". Kind of a more extended, RWBY version of Tekken's Alisa Bosconovitch.

The reason she can use Aura is because it comes from the Soul, but only hypothetically. In reality, Aura comes from the Mind, which is basically what would define one's "Soul". Thing is, it isn't restricted to a biological mind.