User blog comment:B214/Question & Answers 5/@comment-50.108.164.34-20151204041232/@comment-213.120.234.122-20151204225639

Even if by some small chance she did come back, Issei would never accept her, don't forget she completely traumatised him by doing what she did go him and Asia. It took him ages to recover. Another thing, Rias and the other girls would never allow it. They'd probably try to kill her again, especially Rias.