Kaoru Matsubara, transform into Buttercup,Or at least that's how it was, after destruction of her world she was sent into your universe, that seems like in your universe you were the only one to be left alive, you were taking your usual walk after you woke up and you saw buttercup sitting by a vegetable stand in the middle of waterfall, it's up to you if you want to start the journey with her or if you want to ignore her