This Monster Wants to Eat Me, Vol. 4 (manga)

Hinako wants to die, and Shiori wants to devour Hinako’s flesh—the two of them are connected only by the promise to fulfill each other’s wishes. But Hinako is gradually beginning to develop feelings for Shiori that go beyond that of predator and prey. All the while, an ominous new shadow creeps up on Hinako…“I can’t be your friend…”