The Stone of Kuromori

Summary
Ever since Kenny learned that he'd been chosen as bearer of a magical sword, he and his best friend Kiyomi have been protecting the human world from ancient Japanese monsters. But Kiyomi's human soul has been taken from her and only the restoration of the three sacred treasures - the sword, the mirror and the jewel - can save her from transforming into a monster herself. As they complete their mission, they discover that all their actions have been manipulated and an undead army is about to be unleashed upon humankind. The forces of life, with Kenny as their champion, gather their allies for a final showdown.