Hisui no Shizuku: Hiiro no Kakera 2

Suzu's closest older figure, Mao, has vanished. Suzu is called back to her rural hometown to step into Mao's role as Tamayori-hime — the sacred maiden who serves as a living barrier between the community and the wrath of the sea lord, and who may eventually have to give her life to maintain that protection. Suzu arrives with no real understanding of what the role requires, knowing only that she needs to find out what happened to Mao. She is still adjusting to her new situation when the sea lord's demons attack the village. The leader of the demonic forces is Toyotama-hime. Suzu recognizes her immediately: it is Mao.