Wings of darkness

It is said that the fallen, the name of the Valkyrie warrior, lives among humans. As a punishment for letting her mentor Sigrdrifa go on a rampage and killing many warriors on the battlefield whom Odin wanted to live, the fallen understood her mentor's human weakness and sided with Sigrdrifa. As punishment, Odin banished both Valkyries from Valhalla.
Resentment festers in the fallen after what happened, making her question her loyalty to her sister in arms. She has been teaching the humans about sources of magic and helping them surpass their technology advancements. Amongst the other duties, the fallen teach young military cadets the art of combat. She could not unlock her powers since leaving Valhalla, however gods were lurking in the darkness.
Since her mentor vanished into the wild and hostile forests, the fallen teams up with an unlikely friend.
In the tricker god Loki, who is investigating the wolves lurking in the shadows, who wants to devour the sun and the moon, she learns her mentor is alive after they fight, but she has changed into a horrific demonic form, she follows Sigrdrifa trail leading her though the realms of Vanaheim, Niflheim, leading to the Fallen's home realm of Jotunheim, where Loki helps her understand her powers, with renewed determination the fallen must learn about her complex emotions and what she truly values, and where her destiny is.
And whether she should side with Odin or his wife, Freya, and that choice will change the future of the Valkyries.