Van Argiano

Van Argiano is the head scientist studying chiropterans for Cinq Flèches. He was in charge of the development of Delta 67, working under Solomon and with his assistant Archer. After Solomon defected from the group, Amshel appoints him to the head of the Cinq Flèches American branch. Despite knowing their true nature and plans, Van sided with the chiropterans and aided them in their efforts to spread chiropterans around the world. Van is often shown to be eating some kind of hard candy. However, he was betrayed at the Metropolitan Opera House and was not told of the plans to turn people there into chiropterans.

He was left to face the monsters on his own by his American contact, Secretary of Defense Grant, but is saved by David. At the end of the series, he is shown being taken to trial to face charges for his crimes. His assistant Archer is also revealed to be a government appointed investigator who had infiltrated Cinq Flèches to gather evidence.

(Source: Blood+ wiki)