I think I’ve solved the main conundrum of this show. Hinako wants Shiori to eat her, but Shiori first wants Hinako to want to live, so that she’s more delicious. But if that happens, Hinako won’t want to be eaten anymore. Also, she’s worried about leaving Miko behind without a friend. Then the solution is simple: all Hinako has to do once she wants to live again is eat Shiori so that she becomes immortal (because of eating mermaid flesh). After that, she’s pretty much a youkai herself, so Miko probably won’t want to eat her anymore (at least not in that way).

MikoHina lives on forever, Shiori has become a beautiful martyr for the cause, it all works out!