De un artículo sobre las Val'kyr:

Orbs

Once the encounter is started, light and dark orbs spawn from the walls at regular intervals and move randomly around the room. If they touch an opposite-color player, the player takes 7000 damage. To mitigate raid damage from these, healers should attune to the opposite color of the DPS group they are healing and act as soakers for orbs of their color. For example, a light-attuned healer should intercept light orbs headed for the group of dark-attuned DPS attacking Lightbane, but allow the dark orbs through. (Fire Resistance and [Shadow Resistance Aura] may also be helpful, as the light orbs do Fire damage and the dark orbs do Shadow.)
If the orbs touch a same-color buffed player, the player receives a stacking speed and damage buff called Powering Up. At 100 stacks, this will trigger Empowered Light or Empowered Darkness, which increases damage dealt to opposite-color targets by 100% for 20 sec. Thus both DPS and healers should actively seek out orbs of the same color as their essence to acquire this boost.

Mis compañeros de raid comentaron que había orbes pero que no tienen skin, ¿puede ser? Si no, hay una fuente de daño medio irregular en la raid, puede ser el Touch of Light/Darkness pero el Darkness le estaba pegando a auras negras.