Books in the Sengoku Youko series

"The world is divided into two factions: humans and monsters called katawara. Despite being a katawara, Tama loves humans and vows to protect them from evil, even if it means fighting her own kind. Her stepbrother Jinka, however, hates humans, despite mostly being one. The siblings are joined by a cowardly swordsman named Shinsuke. With the Four Beasts of the Dangaishuu defeated, the group is finally on their way to fight the origin of the cruel human-katawara experiments, Lord Yazen. With the end in sight, is a happy ending possible after so much destruction and bloodshed?--Back cover.