Rhayna straightens herself up. “Thank you Joetaro for helping me. Nice Unicorn by the way.”

(OCC. Can Clerics help with the poisoned condition?)

Clerics do have access to the Protection from Poison spell, which can neutralize a poison, but Rhayna does not have it prepared.

Joetaro goes to stand in the doorway with the unicorn to give everyone some room to breathe. Kastix stays alert for danger. The room is quite bare other than the sarcophagi and Zeno quickly determines that none are trapped and can be opened safely, although he detects that the southeast one is built on hidden stone rollers, and can be moved aside. With Rhayna's help, Sekkar and Kaylyn slide the lids off the sarcophagi.

Each sarcophagus contains mummified remains, the tattered remnants of ancient burial garments, and treasure of Netherese origin. The northeast sarcophagus contains two gold bracelets and a wand of chiseled ivory. The northwest sarcophagus contains an onyx ring and a silver necklace set with two azurites and a carnelian. The southwest sarcophagus contains a ewer made of beaten gold and a walking stick made of varnished yew with a golden handle shaped like a scorpion. The southwest sarcophagus contains a gold censer with platinum filigree.

"Wand?" Kastix questions when he see it and will try asking to cast message with it, pointing it at random person and whisper, "Is this working?"

Everything looked quite worthless. Good for selling, of course, needed to be taken for the future exchanges, but after Rhayna's explanations Sekkar expected more from the "ancient magical civilization". And it did not look like an origin of the voice either. There was still the door to the right, of course... When everything was collected by the "backpack bearer", Sekkar moved to the next unexplored door.

Rhayna checks if any if the items have any historical significance.

“There’s the door, but also this sarcophagus moves if we want to see what’s underneath...”

"Do they now..." That was interesting indeed. Sekkar tried to push it.

Rhayna: make a History check

Kastix waves the wand and casts his spell, and Rhayna hears Kastix's voice in her head saying "Is this working?"

Sekkar helps Zeno push the sarcophagus aside, revealing a four-foot-wide square hole in the floor. As light spills into the chamber below, the voice is again heard in everyone's mind: Yes, that's it! I'm here, below! Oh, it's been dark for so long!

Kastix will pocket the wand, "This is definitely useful," before seeing the hole in the floor, "However, that is asking for trouble," 

Rhayna History: 21

Sekkar grinned somewhat eagerly: "Are you thinking we are unleashing an eternal evil, that was kept here by the ancient what's-their-name, on unsuspected murderers citizens of those tunnels? May be it would not be so bad, it might fight that demon thing in the lake." He checked for a traps as well as he could and if everything looked clear, risked to peek inside.

"That demon thing is strongest demon lord in the abyss who somehow made to the Underdark. I doubt anything in a small tomb would fight it," Kastix states as he takes a look into the hole. 

Adding to what Kastix said. "If I am not mistaken, this tomb belongs to a person that passed away hundreds of years ago. I believe."

Looking into each sarcophagus  Kaylyn cast Detect Magic to see if any of the items found are magical.

"If you really want to go down, I can make you invisible now," Kastix really want to use material spellls now that he has a wand.

Sekkar looked at the wand suspiciously: "You sure it will be all that thing do? And you could turn me back? You just found that thing." Invisibility was nice but sometimes you do want to be visible. "If you are sure, we can try but if you turn me into a unicorn - I'll stomp you. Just so you know." Once invisible (and after the peek revealed nothing particularly dangerous) Sekkar will go into the hole.

Kastix will twin the spell and cast Invisibility to turn Sekkar and himself invisible. 

“I’ll give you a headstart, then follow shortly,” Zeno tells the two as they prepare to scout.

Rhayna doesn't recognise anything specific about the items of any historical note, other than they are typical ceremonial burial accouterments for significant servants of a Netherese noble. Her judgment of the tomb however is that it is about a thousand years old, and may have been an example of a flying structure typical of the Netherese empire with their flying cities, but somehow fell deep into the earth following Karsus's Folly. Kaylyn's spell produces no magical aura around any of the items, but does inexplicably produce a small cloud of fluttering butterflies and colourful floating flower petals in the air around her. Zeno swats at them but his hand passes right through, revealing them as mere illusions.

Kastix lays his hand on Sekkar, waves his new wand, incants his spell, and they both suddenly disappear. At the same moment, Joetaro is with the unicorn watching from the corridor (out of smell-range of the others), and hears a soft 'pop' as the unicorn also vanishes.