The Valkyrie's Daughter by Tiana Warner

From the time she was born, Sigrid has only ever been ordinary. Being paired at birth with a plain horse―instead of the powerful winged mare of a valkyrie―meant there would be no warrior path for her. No riding the skies, no glory among the nine worlds. Just the simple, unremarkable life of a stable hand.

Everything changes when a terrible enemy ambushes Vanaheim and Sigrid sees a vision of herself atop a mythical stallion, leading the valkyries into a harrowing battle. Finally, she can grab her future with her own two hands and become the hero of her own story…if she dares.

But her destiny is tied up with Mariam, a fallen valkyrie who’s allied herself with the very enemy Sigrid is trying to stop.

Now Sigrid has left ordinary behind as she begins a journey with the beautiful―if treacherous―valkyrie, each step bringing her closer to answers…and to awakened feelings for Mariam.

Only, the life Sigrid has escaped may have been paradise compared to the one she’s racing toward. Because her destination is the realm of the dead: the gates of Hel.