She was manufactured 30 years ago, and then an immortal mage from the medieval era found her, and gave her life using magic. She is extremely light, given she's full of air, and mana.
@KeonWolf I use a combination of VRoid, and Unity Editor. First I export as a VRM, use UniVRM to put the model into Unity, and then I apply a matcap. For a matcap like this, I go into any image editor, make a 512x 512y size image. The image is all black, with two white faded circles. What this means when read as a matcap: Black (display nothing) White (display a white circle that follows the camera based on the vertex, or pixel data.) Try experimenting with it a little. Have some fun with it.