Was she an anime character? Mascot? Leek farmer? Nope, we now know she is the original Vocaloid. In other words, a fictitious android from the future brought here to make music.
You can also pay money to see holograms of these Vocaloid idols perform on stage. The compromise for Vocaloids not being real people means that they can never really set a bad example to the kids who love them, unlike so many real life celebrities.
Here are some of my favourite Vocaloid songs I have stumbled across recently:
You wouldn't think screaming could be in any way positive for a song like this, but evidently, it can.
Full Moon o Sagashite springs to mind.