A Wolves of Ruin: Dire Bound

Book one of the Wolves of Ruin dark romantasy series by Sable Sorensen. Meryn Cooper has never dreamed of joining the Bonded, the king's elite warriors who form mental links with massive, vicious direwolves, content instead to scrape by in poverty in the shadow of the castle. But when her younger sister is kidnapped by the immortal monsters her kingdom has fought for centuries, Meryn enlists to cross enemy lines and gets far more than she bargained for: deadly trials, uneasy alliances, and an unexpected, dangerous bond with a wild direwolf that may be her only hope of survival. Pitched as a mash-up of Fourth Wing and Game of Thrones.