A clear death flag, but one that can be reverted in a smart way, imagine that Fooly uses his recovery magic to the extent that he injects so much life that makes her...well, you know.
@Bakaman
You forgot about the potential for an open ended ending where you are not fully shown whether one of them is actually dead or not, but is more or less just left it to the readers to decide for themselves. AKA the worst type of ending for a story that didn't have anything like that in its entirety.