This Dark Descent (US)

The Rusel family is famous throughout Enderlain as breeders of enchanted horses, but their prestige is no match for their rising debts. To save her family's ranch, Mikira Rusel is left with only one option: enter the Illinir, a treacherous, cross-country horse race known for its high body count as much as its enticing prize money.

To have any chance of success, Mikira will have to recruit Arielle Kadar, a talented but unlicensed enchanter who creates golems in place of enchanted animals, and Damien Adair, a dashing young lord in the midst of a fierce succession battle. Both have mysterious reasons of their own to help Mikira -- as well as their own blood feuds to avenge.