Velvet & Venom. Bone Mother Chronicles, #1

Ella has spent her life buried in ash. Trapped in a decaying manor ruled by a cruel stepmother and haunted by restless spirits, she survives by staying silent and invisible. But when the kingdom announces the Crescent Moon Ball, Ella makes a desperate bargain with the ancient entity known as the Bone Mother. In exchange for a gown, a carriage, and three nights at the prince's ball, Ella gives up pieces of herself .
her reflection, her memories, and eventually her very identity. Prince Robert carries a curse of his own. Born into a bloodline bound to darkness, the ball is his final chance to find a bride powerful enough to balance the monster growing inside him. The moment Robert and Ella meet, their connection ignites. But magic always demands payment. And the Bone Mother never forgets a debt. In this dark Cinderella retelling, a cursed prince meets the girl the kingdom tried to bury.
Two monsters fall in love . and together they might burn the kingdom to the ground.