Eliminate The Blasphemer.
The only one amongst the Primogenitors who doesn't have a Halo is Emperiti. The other Primogenitors are monarchs except for her. She is here in her partial form which is a cloud of dust. The dust is actually a cloud of tiny living things. They are smaller than mites and present in all her Vampires.
These mites replicate and transmit themselves very quickly. All they need to infect someone is to enter their body through any wound. Then the infected will turn into a Vampire and become one of her numerous thralls. That's why she is called a plague. She spreads Vampirism like a disease.
The Primogenitors are always quiet and regal during these meetings. It is a behavior that they adopted from their previous lives as elves. Elves are always graceful and composed. So they are able to remain composed despite the seriousness of the issue at hand. They are arguing right now but it looks like banter at a party.