Mother by Camilla Lancaster

Nevetharine's memory about her former life has eluded her ever since she first woke up in Vudreigh, an evil fortress in the charge of the sorcerer, Magnus the Mad. With Magnus planning to unleash swarms of demonic armies on the dead, barren world that is Narana, it all looks hopeless for any human race that might have survived his torment.

But Nevetharine soon discovers that Celestial Souls, powerful beings that control much of the universe, are more than just a legend. With the encouragement of her best friend and the help of a strange woman known as "the Witch", she is led on an adventure to seek out the Celestial Souls and their aid. She is particularly interested in the Soul responsible for the wellbeing of Narana. Why has she stopped supporting life on the world? Why hasn't she fought against Magnus? Has she lost her interest in humanity?

This journey will lead her to discover the truth about the Souls - and about herself - that has been hidden from her memory...