A Sakuya-Meirin pair produces a Patchy and then a Remirya... The Sakuya and Meirin are killed... (by a Flan?) A starving Remi eats the ko-patche in her sleep... Then either starves or is killed by Flan, then joins her departed family in the easy place? That's my guess.
The title is "Scarlet Devil Mansion" written in a cutesy way. Given that Remi is shown to be in a not-so-nice situation, she's seeing a vision of a very easy Scarlet Devil Mansion before meeting her last moments.