She's from Vocaloid, it's a music program thing from Japan that is famous for having voice banks, so you have virtual singers, like Miku, the Kagamine twins, etc. she's sorta like a made-up celebrity, like the muppets or Gorillaz. They also have rhythm games and stuff of her, and they even do concerts where she and the other vocaloids perform on stage as holograms! (I've been to one, it was awesome)
