Sisters of the Moon
Sisters of the Moon are the fourth boss of the Tomb of Sargeras raid instance and a real team! Now here is a true display of amazing teamwork, a good example for many parties: even when only one of them gets all the kicks, the others try their best to sugar-coat her suffering.
According to the official backstory, the Sisters have been serving as guardians for the temple for many years and started their service long before Sargeras’ armor was buried there. Surprisingly, they have kept their watch for hundreds of year even in death. However, nothing is perfect, and such an exhausting duty affected the guardians’ minds: they have gone completely insane. Presumably, this is the reason why they keep trying to kill anyone who enters their chamber.
Tactic-wise, the encounter consists of three phases, each of which stars one of the three guardians as the protagonist: one boss is attackable, while the others assists her with their casts.