Qesnef walks over to the safe and begins entering the combination keys to open it, meanwhile he answers all the questions as best as he could, as they came.
"What have you got in there? Are you just here for that sword or is there some other purpose? Can you leave of your own volition? Would you open the safe in a fashion that puts as few people at risk as possible?"
"See for yourself. My room does not lead anywhere else, the way out is back the way you came, which should be open now that you've let me out. The whole point of this dungeon is to collect these powerful weapons. Blackrazor is sentient, was created by the Raven Queen herself! It speaks to me!!! It is precious."
"So, if you don't mind me asking, how did you become trapped in your prison. Did you go inside looking for treasures and find that you could not leave?"
"I came down with several other adventurers, as we formed a crew in Neverwinter. One by one they all died until I was all alone. Finally, I found Blackrazor and then CLICK! Keraptis himself told me he was working on getting new adventurers and that I would have to be the zookeeper until you arrived." He shrugs.
The safe opens to reveal the types of food that manticores, sea lions, scorpions and crawfish eat. It stinks in there. There is nothing of value unless you're really hungry.
27 Anyone who ventures into Qesnef's room (PLEASE BE SPECIFIC WHO WENT IN AND WHO DID NOT)
Lavish furnishings and decorations are everywhere in this large room. The floor is strewn with rugs and cushions, and tapestries cover the walls. A hookah as tall as an adult human stands in one corner. The largest piece of furniture is a sumptuous divan. Anyone with a passive investigation dc15, or who rolls it, finds the divan seats can be pulled open to reveal a treasure stash: 1,000 ep, 200 pp, four pieces of jewelry worth a total of 11,000 gp, a potion of greater healing, a scroll of protection (fiends), and magic plate armor that would fit Kassan, definitely wouldn't fit Qesnef.
BLACKRAZOR:
https://5e.tools/img/adventure/TftYP/WPMBlackrazor.jpg