The Vitriol Fulcrum is not easily described as a person, though she may have been one once. By the time the campaign reaches her, the distinction between her as an individual, her fortress the Shardhold of Silence, and the emotional corruption she radiates across the eighth layer of Hell has blurred past the point where the categories hold. She is person, place, and power simultaneously. The party understood this before they arrived. Understanding it did not make it less disturbing.
Her story, as the party pieced it together, involves a betrayal of sufficient magnitude that it did not simply wound her — it became her. Her tears became the Nihil Shard and whatever other fragments exist connected to it. Each shard is infused with pain, fear, sadness, and rage. Zevron recognized them as keys that could open any lock. Others recognized them as weapons. The Vitriol Fulcrum’s relationship to her own shards is something the party will have to answer in person.
The eighth layer of Hell is frozen because of her. Nothing burns there. The cold, the silence, the half-buried statues locked in expressions of grief and rage — these are the physical consequence of what she carries. The pilgrims who serve the Betrayer travel across that wasteland looking for revelation through suffering. The Lake of Severed Reflections, which showed the party their own most painful memories of betrayal, was shaped by her influence.
When the party underwent their visions at the lake, they awakened her to their presence. Her warriors came immediately — soldiers of betrayal who carried psychic backlash in their deaths. The Herald of the Ivory Labyrinth led them, fought the party across the frozen lake, and ultimately accepted the outcome and escorted the party to the Shardhold.
She knows they are coming. Whether she intends to stop them, to use them, or to simply see what happens when people carrying their own betrayals walk willingly into the heart of hers has not yet been answered.