Hayou no Tsurugi: Shikkoku no Mashou

In feudal Japan, half-demon twins Towa and Setsuna are separated from each other during a forest fire. While desperately searching for her younger sister, Towa wanders into a mysterious tunnel that sends her into present-day Japan, where she is found and raised by Kagome Higurashi’s brother, Sota, and his family. Ten years later, the tunnel that connects the two eras has reopened, allowing Towa to be reunited with Setsuna, who is now a demon slayer working for Kohaku. But to Towa’s shock, Setsuna appears to have lost all memories of her older sister