When the encounter begins one lucky raid member will be chosen to be "the first vampire" - It's going to be whoever is on top of threat meters, after the tank. This party member will enjoy a huge DPS boost but it comes with a price and this is where things get interesting.
When the buff wears off, the raid member will have fifteen short seconds to basically play "tag" with another non-vampire raid member by biting them. This will re-trigger the buff on the original vampire as well, so as the fight goes on you will have more and more vampires, and more and more DPS.
If any of your vampires fail to find a fresh target to bite at the end of their buff cycle, they'll lose control of their character to the Blood Queen and this will essentially wipe your raid, as there's nothing to do but kill the poor insane raider and take the massive DPS loss meaning you'll never get her down in time. Because of the nature of the fight, it's on a hardset timer - if there's no "normies" for your vamps to bite, it's game over.
With this in mind, your DPS vampires should be prioritizing their bites to other DPS - with the healers and tanks being bitten last.

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