With every drop of blood, the tide rises.
The Rising Tide is a secret cult of blood mages and would-be vampires in
Lagash, defying the imperial decree against Blood Magic in search of power and immortality. As the name suggests, they only accept male members of "good breeding and blood", which along with their focus on forbidden, blood-soaked magic make them a real unpleasant bunch. Unfortunately for Lagash's citizens, they are all powerful in either wealth, influence, or arcane talent, providing them ample leverage to find victims for their rites and hide the evidence. Though their goals are simple - power, preferably immortality - they dress it up with elaborate theatrics that real vampires and blood mages find terribly tedious.
Agenda
The Emperor be damned - he think he's the only one allowed true power in the city! Why, doesn't he know who I am?
Convinced that their path to real power lies through Blood Magic, the Rising Tide is obsessed with accumulating any lore it can regarding it. If the Emperor saw fit to forbid it in his city, the cult reasons, then he must fear its true potential. The idea that blood-hungry maniacs running around the city looking for victims to sacrifice, which is the agenda for the next cult meeting, has never really crossed their mind. From esteemed families, the members scarcely see the great herd of citizens within the city as anything more than animals to begin with. If a few dozen - or hundreds, or thousands - have to die to their blood can be tide upon which the cult can rise to power, well... Such is the purpose of an animal.
Every member is given a secret 'blood-name' which serves as their identity within the cult, which are about as embarressing as you'd imagine.
The Cult operates mainly out of the
Arcanium District, meeting in manors, towers, and even in secluded part of the sewers when they feel like slumming it. Tide meetings are rank affairs where members peacock about and vie for dominance within the brotherhood, each taking part of an endless one-upsmanship that would be entertaining were the end results not so grim. Many of its members have become skilled and terrifying wizards, far beyond what their station in the city would suggest - a fact that rankles them to no end. For some of its member, power is the only goal and they have undergone a terrible rite to become vampires. Should their condition ever be discovered, the Emperor's Law would be merciless, given the Emperor's own, stated dislike for bloodsuckers.
The Rising Tide has been infiltrated by vampires from Esarhaddon since the beginning - a task so easy the spy in question scarcely had to try.
And secretly most of the city was filled with bloodless creatures while they whisked away those with blood, to safety quelling the rebellion, and giving the upper hand to the home team. The bloodless then captured and killed the Rising Tide with their own blood.