The committee dodges the first strike. He, however, did not learn from his fallen ally and gets smacked upside the head by the blunt end. 

Concentration: 19, success. 

The younger cultist then runs over to Kess. Does Ada want to make an opportunity attack?

Sure!

Halberd - Attack: 18 Damage: 10

The cultist runs and dives to try and reach Kess in time. He, however, gets caught by Ada's halberd and falls to the ground, dead.

Kess is no longer paralyzed, Chipper's turn.

Withy Kess no longer paralyzed, Chipper begins to sing a discordant melody into the mind of the balding cultist next to her.

Dissonant Whispers @ Balding Cultist //using Fey Touched free cast
Damage: 5+3+6 = 14 psychic damage
INT Save DC 15, half damage on save, must use its reaction to move as far away from Chipper as possible on fail

[[ Using dissonant whispers since it should also trigger an opportunity attack from Kess I believe. Looking for a situation to add another source of damage on top of a spell. ]]

Int save: 13

You see the man clutch his head, as if his mind is being melted inside his skull. You think he was about to turn around and run, but before he can the light leaves his eyes. The final cultist is dead.

Kess lets out a sigh of relief as the paralysis wears off and the last enemy falls. "I hate that spell. At least they put up a fight though." She shrugs and goes to check the bodies for items.

Perception: 16

Razz hovers midair, brushing imaginary dust off his sleeves as he surveys the smoldering remnants of the cultists. With a dramatic sigh, he gestures around the room.

"Well, that was fun. Nothing like a basement full of lunatics, explosions, and questionable life choices. But hey— the only thing left is the furniture and we probably won’t have to fight that."

He pauses for a beat, then tilts his head.

"Unless, of course, Strahd enchanted the wine racks. In which case… I quit."

Each of the cultists had a dagger, leather armor, and a small piece of parchment with a pentagram drawn on it.

Razz will cast guidance and do an arcane check on the pentagrams.  See if he can figure out if the smaller ones were any different from the large one on the floor.

Arcana Check 12 +4(guidance rolled) 16

In shape and design, they're almost identical. However, the magic is very different. The smaller ones feel almost like a holy symbol, but instead of holiness they give off a sense of evil.

Kess goes to look around near the cots for anything.

Perception: 9

Chipper ritual-casts detect magic and begins to look around. First at pentagram symbols.

The smaller ones appear to be spellcasting foci, while the larger one has an aura of conjuration.

There's nothing near the cots.

Razz looks around and wonders if there's anything worth reading in here.

Perception Check: (Nat 20) 22

If he finds anything he'll say the following:
"Hang on, I do have a spell for this! Let me just take ten minutes to ritually prepare myself to read something I probably don’t want to read."
He'll then ritual cast Comprehend Languages

If he doesn't find anything, he'll check on everyone and see how they are doing health wise and see if anyone needs more than the rest AS well as checking on Stella to make sure she's still ok. If he does find something, he'll do this immediately after (unless interrupted)

Seeing that each cultist had a piece of parchment on them, Kess will quickly return upstairs to find the black robe she saw in Fiona's room and check it for anything similar.

You find many books, but they're all in common with similar topics to The Devil You Know. 

The inside of the robe does have similar symbols.

Kessintra returns to the basement with the robe and lays it out so the others can see the symbols. "Does this mean anything to anyone? Maybe with all of these we really could summon a devil...Think it would make a deal to give us some diamonds?"

"It might, but that cultist mentioned Fiona's husband.  We might be better off Not reviving him if he had anything to do with this stuff.  Stella, did you ever see your Dad come down here with Owner?"

Stella seems surprisingly calm about all this. "No. I didn't even know we had a basement."

"I'd prefer not to make any deals with devils if we can avoid that," Ada says dryly.