User blog comment:B214/Volume 21 info & spoilers/@comment-27083298-20160308001905/@comment-26821288-20160308002431

Well, Ishibumi did say that DxD will end with a good ending, so it's most likely that Ophis will survive, in my opinion.

Although, even with that said, it still is possible for Ophis to die. Nevertheless, Ophis already have a death flag over her, and Ishibumi said he planned to have her dying, but seeing how cute she is, he kept her as a mascot character, so it's not really likely that Ophis will die. But, Ophis did take a huge part in DxD, so for her to die will mean taking another huge part in the DxD series, so it's really questionable. Nontheless, I pretty much think that Ophis' chances of survivng are high. My bet is that Ophis will survive, and live.