Yomi no Tsugai

Two twins born in an isolated village lived very different lives. Yuru became a hunter while Asa was trapped in a cage for a mysterious duty. One day, a helicopter called “Dragon” by the villagers came there and started to kill adults in search of Yuru. When he reached to protect Asa, he found her dead, and her killer claimed to be his real twin sister. Yuru was later rescued by an outsider, Dera, but soon they got trapped and were forced to perform a ritual.