The Professional's Vow of Blood (English-dubbed)

Adrian, the deadliest hitman from Villains' Vale, descended from the mountains on a routine mission. But nothing was routine about finding Vivica—the Crime Lord's daughter—poisoned with a lust-inducing toxin. He saved her without a second thought. The Crime Lord was grateful. The reward? Vivica's hand in marriage. But Trenton, the most eligible bachelor of the underworld, had loved Vivica for years. Furious and humiliated, Trenton was dead-set a trap on destroying Adrian. To which, the hitman smiled, "Extermination it is."