Discovery, Exploration
You've found him! Tarul Var, the lich that runs the Doomvault and one of Szass Tam's lieutenants. Surely he will have a glyph key that can get you into the Temples of Extraction and ever closer to the Phylactery Vault.
Finally! Tarul Var and his dread warrior guard stand before you. While Tarul opens with a Fireball in the middle of you all, you soon find out why Szass Tam is upset with him as he proves to be much less of an adversary than you thought he would be.
After finishing off Tarul Var and his dread warriors, you find several letters written by Var to Szass Tam begging for forgiveness and another chance to overthrow the Sword Coast. You also find an ornate iron key along with a glyph key attuned to both the Abyssal Prisons and the Temples of Anguish. Which means you finally have a key attuned to a zone within in the Temples of Extraction.
After returning to the Gatehouse to rest and inform Syranna of Tarul Var’s defeat (at least until his body is recreated near his phylactery) and that you have a way into the part of the Doomvault that reportedly can get you into the Phylactery Vault your use the Black Gates to get into the Temples of Anguish.
The first area you encounter contains a three-step stone dais is set with four pillars, all carved of black jet. Glowing arcane runes surround the top edge of this shrine. Between the pillars, an unconscious humanoid is suspended in a roiling field of golden light.
Additionally, the air in this white marble chamber hangs heavy with a dark mist that burns the eyes. Each of you temporarily succumbs to the effect but recover in time to easily deal with the necromancer and his helm horrors.
Examining the shrine, Malice and Brehana determine that it can be disrupted by smashing the pillars, or removing key runes, or attempting to disrupt the flow of magic. In fact, Pubert take a decent chunk out of one of the pillars but instead of having him finish it and release the Yuan-Ti trapped in it you decide to continue exploring and trying to find more information before deciding what to do about the Shrine.
Naturally the next room you find also contains the same type of shrine but where the first room had a black mist this room has a red mist that appears in the air, as if someone is whipping the air and it is bleeding.