Q stands for Quidel Xhian which is a society of vampires that refuse to take part in the act of drinking blood. It is unlawful and any vampire that drinks blood is a fugitive who the Quidel Xhian will put to death if they are caught.
Although these vampires refuse to participate in such action, they aren’t necessarily the good guys either. They see themselves as better than both blood drinking vampires and humans. They look down on societies and never fail to enjoy raising themselves up on pedestals.
This society has an agenda and wish to implement it and any human or vampire that stands in their way will not be tolerated. They see it as a crime to drink blood but they have no trouble with spilling it with other means. This is the Quidel Xhian, a group to be wary of.