Immediately Barbär thrust his hands outward to stop the party, like a human seat-belt, and scans the room. Perception:

20, Hold! I Don't feel right, here.

The collection of jars includes a cockatrice, a flumph, a giant fire beetle, a small grell, a myconid sprout, a pseudodragon, four severed hands in the same jar, and a demonic looking tadpole that’s still alive. One of the larger jars is open and empty.

What the..

Barbär backs up pushing everyone back and shuts the door!

Everyone, weapons out! Theres movement in here and im sure it isnt nice!

he waits for everyone to ready up, and readies Green-flame Blade for hostile actions inside, and opens the door

‘Wait Barbär. Let me go first...’ says Orvok, before casting Detect Evil and Good. He pauses a moment to see what his new senses detect...

Emporious will move in when his turn in the procession arrives. 

The hands in the jar are screaming undead and evil. Well, they're not screaming, they're disembodied hands. The room is the same as it was a moment ago. The tadpole, of..whatever that is..squirms a bit.

‘I’m not sensing fiends just now. The hands are undead, and the tadpole is something else entirely. Illithid perhaps?’ Orvok steps further into the room, straining his senses for a threat...

Perception: 19

Barbär pushes in as well, still readied

"Ooooooh, hands and baby frogs.  Scary." Hino deadpans.

Isa follows in step to enter the room with her staff in her right hand - she is ready to cast Fire bolt if needed.

"It would appear that we have a new suspect in the case of "who murdered the mage". If no one sees any books might I suggest we move back up stairs." Offers Emporious after giving the place his own once over.

Perception: 23

Nothing here except the empty open jar and the other samples.

As Orvok slowly, carefully, leads the group back up to M5, he shares some thoughts ‘It strikes me that this Fistandia was a dabbler in dark magics - there may be other nasty surprises to come...’ and then ‘Even if we work out how to leave, we can’t risk whatever killed Matreus escaping with us... We’ll need to either make sure it’s dead, or ensure it can’t hear or see us when we leave...’

Perception: 6

Oh dear. Another nail-biter, but this one is worse than the damned Raven house! Im just a bit on edge since Matreous died..

(the body is still there, yes? And the wound hasn't gotten any worse? Perception 5 )

As they make their way up to M5, Hino will keep her eye and ear receptors open and scanning for anything (like a curtain, mote of dust, etc.) moving, betraying something invisible following them around (Perception: 7).

Isa follows along behind Emporious as they make their way back to the study (M5).  "This Fistandia was definitely dabbling in some dark magic... summoning cirlce, creatures in containers, alchemy and trying to turn things into gold..." she gives a short nervous chuckle "that looked like a spectacular failure.... not that I could do it either - but why would this Fistandia be trying to turn things into gold or summon some awful creature, let alone keep dead ones in containers?!"  Giving a slight shudder "Those last two kinda freak me out a bit."

"Dark magic? or perhaps just research....I mean if Mystra granted this Fistandia a permanent extra dimensional space for their mansion there had to be a reason.  Not everything is inherently evil..despite how it may look." and Mav will let that hang in the air and look around at his companions, especially Isa.

Avoiding Mav's gaze at her, Isa replies "It still freaks me out a bit.... and I find it hard to believe that this Fistandia is a good person if they are summoning creatures and keeping them in jars... In my experience, if it looks evil then it probably is evil... Regardless of what Fistandia was doing here, we need to find the rest of these books so that we can open the portal to get out of here and hopefully find someone else that can help us with figuring out how we can help Emporious and the people of Altus."

Not everyone does things of their own will either. She could have been made a pawn by something dark and terrible. If my research proves true, demons of the nine hells operate by contract, sometimes the way out of a contract is to offer a large amount of gold, or any form of bartering, if you have something your demon is interested in.