You were Sayaka Miki, one of the Law of Cycle's or Madoka Kaname's personal cabinet, the other one was Nagisa Momoe.

Being taken in by Madoka meant as a puella magi, you could switch between your normal form and your witch form. Your witch is Oktavia Von Seckendorff, the mermaid witch. You can summon her if you're near a pool of water, or by stabbing your heart out.

Madoka saw a universe which had many despair, as hope itself she made it her mission to save everyone. She gave this universe to you, and told you: "Please, Sayaka. Save this universe from its wrath." Madoka gave you information about this new universe, so you could have a basic understanding of it.

You landed in a new land, this place called "Hueco Mundo". Home to Hollows.

You walked, killing the hollows that stood in your way. That was until you saw a fight, in the distant. You saw an orange haired vasto lorde, he was charging up a cero towards the 4th espada, Ulquiorra Cifer.

Although arrancars were bad, you felt this Ulquiorra was different, he felt like the most human hollow, you couldn't let this slide, you were one of the Law of Cycle's personal cabinet, so when that cero was coming towards Ulquiorra, you run in and block that cero with your cutlass, letting the cero go the other way.

Ulquiorra looked surprised, including other people too, which were Orihime Inoue, a healer who was kidnapped, and Uyru Ishida, a quincy on the shinigami's side. Who could blame them though? You're a person who isn't wearing a quincy, arrancar, nor shinigami uniform.