The Roar of Smoke, A book of the Meldborn

Tressida is a smoke-spinner, a meldborn. It's a lethal legacy, a forbidden force. Daughter of Crone and Sage, she should have been killed at birth.
 
Now she's seventeen, wanting only to be a member of her land's vanished Horseguard and discovering she is more than she ever knew, as first her eyes and then her hair turn to smoke. Just as she learns she can fulfill her dream of working with horses, her talent awakens an ancient and deadly feud.
 
On one side—those claiming the honor of destroying a meldborn. On the other—those intending to use her for their own ends. Tressida must master her power in order to save herself and those she loves. Is she strong enough?
 
Or will the roar of smoke consume her?