Magatsuhi

Magatsuhi summary:

From MangaUpdates: Outcast... Accursed... Long ago when the gods dwelled in the mountains, the fief of Miyoshi is overrun and Princess Miyoshi flees to safety. But she is pursued by the Magatsuhi ("Devil's Masks"), powerful spirits who possess human bodies and foment rebellion and assassination. Then a mysterious girl, Kagachi, with strange powers appears to protect the princess. But could it be she's also one of them...?