Shadowlands Omega by Elizabeth Stephens

“I look forward to punishing you, Kiandah.”
“You’re a cruel lord.”
“A hero would have no chance with you, so for you, I will be the villain.”
After burning her church to the ground and throwing her family into the castle dungeons for their treason, Kiandah did not expect to be spared by Lord Yaron, the Berserker Lord who once vowed — and tried — to kill her.
But as Gatamora’s newest ascended omega, and a traitor besides, Yaron finds that Kiandah may be best placed to help him root out the source of the danger encroaching on his territory in the south island. Rumblings of a sinister sort have reached him…rumors of the undead and witches…
The only trouble will be keeping his distance. Shadow Lords do not take ladies, least of all peasants and criminals like Kiandah. But as her power over flame continues to grow stronger and the threat of the undead draws ever nearer, Yaron may have to choose — to succumb to her heat and save Gatamora together, or let it all burn.
Burn Omega, burn.