I am sure this one is pretty simple.
Blood sucking evil. Ruled by a Queen. If you kill the Queen her “minions” die with her. Those who have been turned but not taken blood/life will revert back to being whatever it was they were before.
They are mid-level demons that were out lawed.
When a man made a deal with the devil, he created vampires. They feast on blood, dislike sunlight and cannot be seen in silver backed objects.
And obviously, you want to kill one, aim for the heart with a stake.