Got to chatting with some friends and I’ve got some HEADCANONS. What? No, not about the remake. About Dirge, of course!
So, Lucrecia, Sephiroth, Chaos, Protomateria.Â
We know the Protomateria is what keeps Chaos under control in Vincent’s body. Lucrecia used it on an apparent whim when nothing else would work. But where the hell did she get the Protomateria, and what was she doing with it, as 1) its only purpose seems to be “restrict the apocalypse” and 2) humans can’t fuse materia into their bodies without serious repercussions.
Perhaps it was a family heirloom and the whole Crescent line were obsessed with Chaos. Probably not. Perhaps she found it somewhere along the way in her quest to find Chaos. Possibly. Perhaps she found it in the cave with Grimoire. Maybe he found it and gave it to her as a keepsake. Whatever the case, she had the thing.
Now suppose it was on her person when Chaos attacked - and that it protected her from the blast that killed Grimoire. Then it became a grim lucky charm. She kept it with her all through her pregnancy. And perhaps it suppressed the J cells enough to allow Lucrecia to survive and deliver a healthy one-winged baby.
Taking this headcanon a little further, let’s say after Sephiroth was taken from her, she chucked the materia in a fit of emotion. It might hit a wall, bounce to the floor, and sit there for a good long time. She might just forget all about it until she’s fished Vincent’s corpse out of the garbage, experimented on him to hell and back, and is now throwing a tantrum (as mad scientists do) because she can’t get Chaos to stabilize inside Vincent. She sees it, reflects on the superstition she had during her pregnancy, and thinks, “Well, nothing else has worked...”