Rei Yume

Rei Yumi is an Arrancar who has the strange power to use Zanpakutou abilities such as Shikai and Bankai, while being able to use Resurrección as well

History
Even though she looks and says she's an Arrancar, she doesn't remember being a Hollow and she has never seen Hueco Mundo, only the human world. Being alone in the human world, she met another soul, a Shinigami named Marinese Kota and the two became fast friends.Together they fought Hollows, until one day a Vasto Lorde appeared, and killed Marinese, and nearly killed Rei. From that day Rei has been alone, and has trained herself to use Shikai, and to fully use her Resurrección with full control.

The Vizards
Rei has encountered the new group of Vizards since she has been on her on her own, though she doesn't know any of their names. She tried to challenge them, but was too weak to beat them. She has tried to join their group, but she doesn't know where to look for them.