In 1025, he convinced a disillusioned Gregorio to leave the Church and join him in Venice. Gregorio threw himself into the study of magic and the two of them made a pilgrimage, along with twenty others, to Constantinople the next year, to summon power beyond their wildest dreams. Without the knowledge of the others, Danilo changed his part in the ritual. Instead of the minor demon they were prepared for, a far more powerful demon was summoned and it overwhelmed them. They all left Constantinople the next night, and by then each knew that something was wrong with them. They were ravenous but they couldn't eat, the food sickened them. They were parched with thirst, but water acted as poison, and more than one of the twenty-two were helpless in the hands of their servants as they made their way back to their homes in Europe and the east. Christian, and to a lesser degree Jewish and Muslim symbols burned their skin. The sun burned them in seconds. As sick and weak as they were, they didn't die, but just grew more and more wizened, like living mummies. And their blood relatives were affected as well.
By the time Danilo and Gregorio made it back to Venice, they were very weak and depended wholly on their servants to bring them back to their home and hide them from the sun and the curious. Both of them poured over Danilo's collection of books, looking for a solution to the curse, and it was Danilo who came up with the demon they set out to summon. Their servants were sacrificed to satisfy the demon's hunger, and in exchange for their souls, each of the cursed were given new strength. Fangs, in order to hunt blood to satisfy their hunger. Increased speed and strength. Greatly increased stamina. Immortality. Their bodies would heal any wound, save for a stake through the heart (which disrupted the pact), decapitation, fire, the sun, and severe water poisoning. They were still subject to the Curse, and they had to learn to control their blood hunger or one vampire could easily drain an entire village and not slake his thirst.
Most of the original vampires and their families were highly territorial and seldom traveled for any reason, except for Council meetings, held in Venice, a central location for all of them. As the family claiming Venice, the D'Ambrosio family has long taken a neutral stance in the Council, looking ahead to the good of all vampires, rather than their own advancement. While his brother studied magic and science, attempting to rid them of the Curse, Danilo continued dabbling in politics. He's played a role in the government of Venice, overtly or in the shadows, for a thousand years.
In modern times, Danilo D'Ambrosio is a member of the City Committee, serving directly under the mayor of Venice. He is married to an American, Kelly Woods D'Ambrosio, and they have three children together. He also has a grown son living in Canada and another living in London.
The family has a summer house in Belluno and often move between the two homes in order to escape the notice of the normal populace. As senior members of the Council, Gregorio and Danilo often quietly investigate matters that the Council deems too dangerous or sensitive for the Sanguinarium, the Council's volunteer force, to investigate.
The Ambrosius Group is what happened to Danilo's shipping business. The company no longer produces or ships goods of its own, but instead is a holding company. It owns controlling interests in many other companies, including Alberici Group, the pharmaceutical company where Gregorio runs his tests on the vampiric condition.