Sawako

The teacher of Junpei and Kanta. She helps Tatsuo with the supply cave until she was entrusted to keep his boys safe before he was captured and sent to a prisoner camp on the same main land the group later find themselves at. Due to her feelings of love for Tatsuo, she is the object of Hideo's jealousy that sent him off. Throughout the movie, she is seen as something like the mother for these two boys, giving up what she can to keep them alive and as happy as they can be.

(Source: Wikipedia)