"Hm. I'm not sure I trust your assessment of his character. I would have figured you were worthy, after all. Who's to say he'll do any better. We should check. Take us to him."

“He is in the storage room with the slave… ought I to call him, or… I’ll take you to him I suppose.” 

The storage room is larger than the priest’s quarters, but not by much. Mouldering crates lie all about, as well as a not-quite-large-enough rust-reddened cage. A bound, gagged, and blindfolded half-elven girl trembles within. A large man in the same profaned ocher robes sits on a crate nearby, scarred hands whittling away, a small mountain of wood shavings about his feet. 

"He has potential, but he'll need to be tested. Explain the issue to him."

The priest explains with that deep compelling orrator’s voice- about how the Doom requires a worthier sacrifice than a slave, about the speaker’s peerless dedication. 

The speaker stands proudly. “I would be honored to serve,” he bows his head. 

“Right,” the girl hefts her preternaturally keen sword. “One butchery, coming right up.” 

“Ah,” the speaker smiles. “Beautiful child… I see our lord of madness has already touched the princess’s mind. Truly our victory is assured.” 

“Oh she’s crazy,” the girl snarls “Oh she’s… shut up about the crazy! Everyone knows I’m the princess with the broken brain. It’s not news anymore! Well she’s not a princess anymore, and she’s tired of hearing how crazy she is!”

The girl rams her blade through the man’s shoulder, pins him to the crate behind. “Voice?” She says. “Hurt him.” 

The voice will oblige.

The speaker suffers a truly astonishing amount of pain before recanting, but their faith is about madness and death. Agony eventually breaks it. 

"No, priest, you seem to have been wrong. This one was not worthy. Speaker, you have a chance to redeem yourself. Who here is more loyal than you? Find them for us."

The speaker is not yet verbal, gasping and panting long after his wounds are closed. 

The priest glances at the ruin of his speaker, bites his lip. “What? Um… the acolyte of the abyss, I would suppose?” 

They can give him a moment, but the voice doesn't have much regard for the feelings of wayward cultists.

"An acolyte? We shall see."

She is a short, reedy little acolyte in stained ocher robes. One could be forgiven for assuming she has gnomish or halfling blood somewhere in her ancestry, but otherwise unremarkable features. 

“Priest,” she bows as she enters. “Speaker,” she bows somewhat less deeply. “How may your humble servant assist you?” 

"We seek one who is worthy. Are you worthy, child?"

“Probably not,” the acolyte replies, “but I am willing to try. What must I do?” 

"Your god is one of madness and oblivion. We must test your limits, and see where your faith falls between those lines. Priest, you should take responsibility for this search."

The priest takes some convincing, but not as much as might be expected. Certainly he is more comfortable dealing pain than receiving it, and is as enthusiastic about drowning others as he was horrified of drowning himself. 

The acolyte breaks quickly. 

"Disappointing. We may need to be more efficient. Call the flock together for the sacrifice, we shall proceed when we have more candidates available."

The flock is called- those who are present, that is. The commotion in the store above prevents summoning those members who are not currently within the cave complex. 

Good enough.

Encourage them to continue testing their preferred candidates.

They do, but it becomes increasingly obvious that they are only doing so from fear, and that fear has begun to fade. 

Nonetheless, torture happens and devoted cultists recant their beliefs after shorter and shorter experiences of agony. 

“Enough,” the priest says eventually, likely recalling his own experiences and his assumption that the girl and her voice are not in fact sent by his god. “My children, listen. We have been tried. We have been tested…” 

The girl stabs him through his open mouth, and watches with mild amusement as he drowns on his own blood. “Right,” she says. “Well. They stopped cooperating. Bloodbath time?” 

We can do a little more! Say something to the lesser cultists about how you have rescued them from the tyranny of their leaders, who would sacrifice them to save themselves from a bit of pain. We've got some good betrayals so far, but I think we still need the lay flock to betray their priests. Oh, and we need to find something to light on fire.

“Umm, disregard the bloodbath talk,” the girl informs the crowd very seriously, because that’s how sister is always so believable. “We rescued you from your priest. He was going to sacrifice you just to save home self a bit of pain. Whereas the voice in my head wants me to find some things to burn so I can sacrifice you just because.” 

Eh, good enough. Light a fire and kill them all.