Moribito

From Scholastic: Balsa was a wanderer and warrior for hire. Then she rescued a boy flung into a raging river - and at that moment, her destiny changed. Now Balsa must protect the boy - the Prince Chagum - on his quest to deliver the great egg of the water spirit to its source in the sea. As they travel across the land of Yogo and discover the truth about the spirit, they find themselves hunted by two deadly enemies: the egg-eating monster Rarunga and the prince's own father. A 10-book series with multiple side stories and a cookbook.

A prequel (with the same character designs as the anime) that takes place six years before "Guardian of the Spirit", this is the origin story for Jin, one of the Imperial Hunters. Prepare to see a fairly normal, slightly-spoiled tween be transformed into a small emotionally-unstable murderer following repeated tragedy. Contains: court intrigue, child abuse, young romance, tsundere, bullying, attempted murder, actual murder, and some seriously messed-up parenting. The story also features Hyoku, another Hunter, who is the same age as Jin; the other Hunters and the Master Star Reader appear as well, and the Emperor and his sons have very small cameos. From the book jacket: Another “Guardian of the Spirit” world!! Lost boy Taiga suddenly becomes the Hunter Jin. The future Hunter Hyoku, Suyou trains as much as possible. Together they will confront a fiery conspiracy in the palace! The secret past of the “Guardian of the Spirit” character, Jin the Hunter. Completely original story.

Manga adaptation of the novel "Yami no Moribito", which is the second novel in the Moribito series after "Seirei no Moribito". All the Moribito novels have standalone plots. After the events of Seirei no Moribito, Balsa returns to her birthplace in Kanbal to revisit her past with Jiguro, the man who raised her. When she finds out that he has been implicated for the death of the king, she fights to clear his name, and on the way uncovers the hidden part of Kanbal.