My Hired Bodyguard Is the Original Vampire

Isabella, the heiress of the Stirling family, dumps Louis, the bodyguard she had kept for three years, only to catch her fiancé, Karl, cheating with her illegitimate sister. After calling off the engagement, Louis forces his way in as her companion for the Blood Banquet with a crazy attitude. At the banquet, Isabella's sacrificial offering is destroyed, forcing her to slit her wrist, and her rare bloodline ignites the appetite of all the vampires present. At the critical moment, Louis releases his primordial ancestor(coercive pressure) to instantly crush the entire room, and a terrified Karl exposes his identity as a "Blood-Eating Heretic." Facing Karl's provocation, Louis uses Absolute Command to crush Karl's knees, forcing him to a kneel. Getting humiliated and angry, Karl attempts to sacrifice Isabella. Enraged, Louis publicly uses "Fang Reversal Counter-feeding" to forcibly mark Karl as his exclusive blood slave, and entraps Isabella into his underground secret chamber to thoroughly claim her.