The Sinclair family are among the first generation of vampires in history, as such they are widely regarded as one of, if not the, most powerful vampire coven in the world and coming second to Count Dracula himself. The Sinclairs were formed shortly during the late 15th century. The first members of this family was a man named Thomas and his wife Esther.
Esther longed for a family, though, after over a year of marriage, she found herself barren. Thomas was on the verge of yielding since he saw his attempts of making a family futile and in vain. However, it was not long until Thomas ran into a man during his return from his veteran duties. This man, aware of Thomas' plight, promised to give the latter the family he desired but at a price. Thomas agreed almost instantly, seemingly not caring for the price. Unbeknownst to Thomas until it was too late, this man revealed himself to be Dracula. The price: Thomas' blood.
Dracula attacked Thomas and bit him, in the process transforming him into one of the very first vampires. When Thomas returned home, he found his wife in bed and severe depression. Under the influence of his newfound vampiric power, Thomas in turn bit his Esther and transformed her into a vampire as well. Eventually, both Sinclairs realized that if they are unable to produce biological children, they would instead create children of their own with the power they now wield.
Over the years, the Sinclair family was born and cemented their legacy in history by being among the strongest vampire coven in the world. There are currently twenty three members in the Sinclair family, with five being the main branch and the others being the second branch.
Unlike most vampires, the Sinclairs are not particulary violent and destructive to where they wander about and attack innocent humans. It is because of this that organizations who are dedicated to hunting and destroying the vampire menace do not register them as a threat. However, the Sinclairs have been known to attack and kill criminals and even other vampires whom sully the legacy of the latter. And some members, specifically the main branch, are well known for being psychotic and violent yet hide this through a rather innocent and calm nature.