Merciless King is the third book in the Blackmoor Heirs series by Ivy Thorn. It’s a dark, reverse harem romance that probe into themes of transformation and redemption. The story follows characters who, though not born cruel, become hardened and ruthless due to their circumstances. However, a significant event leads to a change of heart, particularly for the characters Cayde and Dean, who shift from tormentors to protectors.