Crescent Pale Mist

Yunou, our heroine of this story, is a magician who is capable of using a deadly and forbidden form of magic known as Pale Mist — the very same Pale Mist that's seeping from Gasyukal — believes there's something more that's causing these deaths. She sets out to seek the source of the Pale Mist and put an end to it, although it's a quest that's easier said than done considering the many dangerous monsters and her former comrades she will confront along the way. (TVTropes)