Kill Streak

When you first enter the room, there's a burning diary in the brazier on the left as seen in this screenshot. This is where it is on the map if you're having trouble finding it.

When clicked the boss will immediately be pulled, jumping at the person who clicked it and oneshotting them while also gaining a stack of [spell=462139]. This debuff needs to be maintained with a steady stream of chumps valiant team players dying throughout the fight. The debuff lasts 45 seconds so someone needs to die at least that often. Since the boss is fairly low damage, we found the best way to refresh it was to assign one person to die to the [spell=437620] each set. These rifts are dropped on random people and then pull players towards them, killing anyone who walks into one. Pick one person per set and send them into one and the debuff should refresh with 15-20 seconds left.

With smaller group sizes you may be forced to cut the refreshing a little closer, meaning you might have to try to use other mechanics like [spell=438245] but these don't do much damage so it may be hard to use them. We had a group of 29 so throwing bodies at it wasn't a big deal.

During the intermission phase the boss will go more than 45 seconds between rift sets so you'll want to pick a person and murder them with [spell=435486] and [spell=434645] instead. On our first pull we had someone die in this way and it did not refresh the debuff so it's worth having a backup person picked to die in case the first one doesn't refresh the debuff.

So long as the boss dies with the buff still active, you get the achievement. Dead people will not get the achievement. (Kidding, though that would have been HILARIOUS).

EDIT 10/09/24: It appears the debuff is longer for smaller group sizes to give them more time between sacrifices, and with a 10 man group it's closer to 80 seconds. This mean you'd only have to sacrifice someone every second set of rifts. We did ours with 29 so your mileage may vary using our strat and you may have to feel out when you want people dying with various group sizes. If you're having difficulty don't forget many classes can taunt the boss and get meleed to death or take a Chasmal Gash as well.

If you have questions about the metas feel free to add me to Btag or Discord!
Btag - FrostyShot#1667
Discord - yarini

When you enter the room, there is a diary in the first fire brazier on the left, read the book inside to give her the kill streak buff THIS STARTS THE ENCOUNTER AND YOU WILL DIE,
then simply kill the boss as normal BUT you have to keep steadily sacrifice people to refresh the buff

WIth enough dps (about 13.7M raidwide) we killed her during intermission with 20 seconds left on the debuff, after someone dying to the previous set of black holes.