Each time Rishe died, it was either illness, war, murder or starvation. Ironically representing the Four Horsmen of the Apocalypse.
The Opening Song title "another birthday" makes sense in that Rishe has had 30 of them in six loops; mentally and spiritually she's 47.
Based on an isekai fantasy light novel series written by Amekawa Touko and illustrated by Hachipisu Wan.