Yondra used her tier four darkness magic spell, Black Heart. The glass was likely to be immune to lightning, whereas fire and ice would give those poor souls a slow, painful death. Plus, there was no earth to manipulate in the chamber.
Darkness was the most humane means to put them out of their misery.
When the energy mass struck the tank, instead of passing through the liquid and killing the orc like it was supposed to, it was completely absorbed by the tank and turned into nourishment.
The liquid surrounding the orc turned muddy and so did the other five tanks.
"I'm quite sure that's not water." Yondra said while trying to understand what was happening.
Thanks to the mana now coursing through the transparent liquid, Lith could see with Life Vision that the six tanks were actually one system and that one of the creatures belonging to an unknown race was absorbing the darkness energy.
