Been awhile since I've done a doujin, so this may appear simplistic. Again, apologies for the lack of screentones; they're allergic to me or something.

In my personal fic universe, Shera will leave Cid soon after the Jenova wars to assist Reeve in WRO. She'll do so for many reasons, the main one being Geostigma. Thinking that she's living under a death sentence, Shera wanted to spend her remaining lifetime doing something worthwhile and left on her own terms rather than become even more of an outcast in Rocket Town. As you can see, Cid is not pleased at all with her decision.

(Yes, Shera is one of the rare few adults afflicted with Geostigma. It was mentioned in the 'Case of Barret' novella. No doubt some fans are estatic about that piece of news, even though she survives.)