Chill works at the lock of the iron chest for about a minute before he hears the soft click he has been working towards.  Opening the lid he finds the safe contains a bag of holding, inside which are four amethysts (100 gp each) and a ring with two ram heads

With that done you make your way carefully down the passageway that Gorrah searched earlier. The kobold with the red eyes is gone and even stopping to listen for it reveals no sounds.  The chamber is empty and you can move on to the next. This leads you to the east and into the room Chill looked into from atop the 20 foot drop.

Sparkling icicles as long as longswords cling to the forty-foot-high roof of this cavern, the floor of which is strewn with frost-covered blocks of stone and a toppled pillar. Embedded in the east wall is a glittering stone tower that appears to have crashed through the ceiling long ago. The exposed wall is cracked and has a few small holes in it but is otherwise intact.

The following features are common throughout the Caves of Hunger:

Ceilings. Most cavern ceilings are 30 feet high and made of smooth ice. Tunnel ceilings range from 10 to 15 feet high unless otherwise noted.

Darkness. All areas are cast in complete darkness unless otherwise noted.

Echoes. Sound travels quickly here. All Wisdom (Perception) checks to hear sounds in these caves have advantage.

"Good find Chill, that ring could be enchanted, I'll identify it later." says Krom as the group makes their way through the passageway. 

"So far, no signs of kobolds, I'm not sure if we should take it as a good sign or not. Anyway, shall we explore that tower over there? It could be part of the lost city." 

"Given the peculiarities with hat kobold, it is most certainly not a good sign. BUT, that is neither here or there for the moment.... Speaking, however,  of enchantments, I should probably have this going as we go, considering we may very well find plenty of other magical sundries lost in the ice along the way." Rhogar proceeds to fish around in his jacket pocket for a time, before finally fishing out a familiar wand and immediately activating it.

"There now. But, uhm... as for the tower, I don't see much in the way of egress there 'save those holes. Gorrah could perhaps squeeze through the largest one, but without knocking down the wall, I don't see the rest following her inside. Although.... hmm.... We'll let's see if its even worth the effort." Rhogar side-eyes Gorrah, who in turn pantomimed a sigh prior to taking flight and swooping her way over to one of the holes to try and squeeze her cat-like frame on through for a closer look inside.

-Gorrah Perception: 23. 
(Assuming she's able to squeeze through holes and into the tower proper. 'cause given the image and wording, doesn't look like there's a regular means of access. And as a note, she is consider a tiny creature)

(Krom remembers that he had an awesome looking belt, and gave it Kazri.)

Kazri puts in the belt given by Krom, and extinguish the flame from the lantern (after checking for hidden things at their location.) It takes a little to adjust to the fact that she is able to see in the dark now. “Thank you Master Krom. It is good that I don’t have to depend on light now.” Kazri wears her shield back, and scans the room for any danger.

Chill looks around the room.  Seeing the others turning their attention to the tower he moves to the passage that runs to the south and watches it.  He listens carefully as he waits. 

Perception 27

"Even if I haven't prepared the hymn specifically created for molding stone, I should be able to create a passageway." replies Krom as he walks towards the tower reviewing in his mind the hymns of fabrication and creation.   "Both hymns will require us to stay here at least a few minutes as they are complex. Maybe I could enlarge those openings using a more mundane mean." Krom places his hand on the head of the hammer. The dwarf begins to examine the openings trying to find a suitable place. ( stonecunning, 13 - guidance 3)

"That belt suits you lass, it gives you a dwarvish look." Nods with approval Krom as Kazri puts on the enchanted belt. 

Chill positions himself by the passage that slopes down to the south.  He listens carefully but hears nothing.  The remainder of the party starts making their way towards the ruined tower.  As they do so they hear something above them and looking up they see several Ice Mephit that begin dislodging large icicles that fall towards you.

Everyone but Chill make a DC 12 Dexterity saving throw or take 7 piercing damage.

Vellynne - 18

Combat - party first (any order), then 7 Ice Mephits

Rhogar's Dex Save(DC 12): 19.

Gorrah Dex Save(DC 12): 3.

Rhogar, in a surprising turn of events, manages to nimbly dodge several falling icicles, but Gorrah is not so lucky. For in her eagerness to try and rush to the tower, she instead found herself nearly impaled into the ground from one of several. As things yet stood, just the share weight of one brushing into her does just about the same, mewling on the frozen floor mewling and trying to reorient herself. 

"Curse these frozen jesters! Gorrah! Focus up! Continue to the tower." The Dragonborn demands, shaking the psuedodragon from her stupor, and spurring her soon after to make a clumsy attempt at flying for one of the tower holes. Rhogar sees none of it however, having immediately set his sights once more on the Mephits above after giving the command, and with a growled out word of power in draconic, summoned localized columns of bright blue flames upon them.

Action(Rhogar): Twinned(1sp) cast (Cantrip)Scorching Grace. Dex Save(DC 16) to 2 of the Ice Mephits, or they take 4 Radiant Damage.

Movement(Gorrah): Flying remaining way to the tower and attempt to squeeze through one of the holes.
(She'll also Dash if necessary to complete the attempt)

Kazri DEX Save: 24

(If anyone is withing 10ft of Kazri, they can add +3 to their saving throws.)

Kazri manages to dodge the icicles and rushes towards the Ice Mephits. (Are they ground level?)

Krom attempts to use his shield to protect himself from the falling icicles. "You will not stop us!" says the dwarf at the ice mephits while moving towards the tower. Krom as he walks, grabs one of the throwing axes that dangles from his belt and hulrs it at the nearest ice creature with all his strength.

Krom Dex save (I assume he is close to Kazri as he gave her the belt) 5

Hand axe (Throw) Attack: 29 Damage: 15 + 7 of Fire damage from Divine strike
(@DM I'll make another roll in case the nearest Ice Mephit is not within 20ft, please consider the lowest roll in that case: 26)

Chill hears the crashing sounds of falling icicles abs the yells from his companions.   Turning his attention away from the tunnel passage he sees the ice mephits up near the ceiling. 

Taking careful aim with his crossbow he fires at one of them

Steady aim

Attack: 17 Damage: 26

Quote from Wolfy911 >>

Kazri manages to dodge the icicles and rushes towards the Ice Mephits. (Are they ground level?)

 They loosed icicles from the ceiling that is 40 feet up so my guess is they are up there and not at ground level. 

(I kinda figured.)

Kazri remembers about the boomerang while searching for the Driftglobe, so she takes one and tries to hit on the frozen flying creatures.

Boomerang Attack: 19 Damage: 4

 Dex Save(DC 16) to 2 of the Ice Mephits 9 12

Vellynee Attack: 10 Damage: 11

19

Attack: 21 Damage: 9

Chill fires a bolt up at the Ice Mephits who are indeed up near the ceiling (40 feet).  The ice mephit explodes as it dies and jagged shards of ice tinkle to the ground harmlessly.  But you recall your previous encounters with these creatures and know that those shards are like daggers if you are within 5 feet when they explode.

Both Kazri and Krom land blows, the fire from Krom's strike as well as the bludgeoning from Kazri's doing more damage.  One ice mephit dodges Rhogars attack while Vellynne creates a skeletal hand that grabs one of the ice mephits as the creature hisses in pain.  

Gorrah reaches the small holes that are big enough for her to fit through and she is about to climb into the tower when she sees something that momentarily terrifies her.  A creature appears before her and she is out of its reach unless she climbs further in.

 The creature emits a bone-chilling cackle that echoes around the chamber.

3

The room all of you stand in suddenly fills with a dense fog and everything becomes heavily obscured.  

A heavily obscured area—such as darkness, opaque fog, or dense foliage—blocks vision entirely. A creature effectively suffers from the [condition]blinded[condition] condition when trying to see something in that area.

Blinded
A blinded creature can’t see and automatically fails any ability check that requires sight.
Attack rolls against the creature have advantage, and the creature’s attack rolls have disadvantage.

Everyone roll a DC 15 Wisdom saving throw or become frightened for 1 minute. You can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. 

So roll one now, and then another if you didn't pass after your next action

Vellynne 7

Frightened
A frightened creature has disadvantage on ability checks and attack rolls while the source of its fear is within line of sight. (not active since you can't see anything right now)
The creature can't willingly move closer to the source of its fear.

(OOC: Gorrah would certainly NOT go any closer, and in fact would spend extra movement remaining to get just far enough away from the holes as to avoid having the creature reach out and still attack her.)

Gorrah's Wis Save(DC 15): 21. (And safe to presume the fear cause is not from a spell or magic effect, so no adv)
Rhogar's Wis Save(DC 15): 20.

Shaken more than he cared to ever admit, Rhogar bad Gorrah to return to his side, trusting her senses in the fog as he had once done so with the white dragon. "Damnable fog! We need to away from this area. That is, assuming you have not the means to dispel it already, Master Krom?" He questions. But rather than linger and wait for word, the draconic duo would begin making their way as best as they could towards the southern exit spied previously in entering the room.

Movement(Gorrah): Return to Rhogar's shoulder.

Movement(Rhogar): Into entryway of Southern Tunnel from current chamber, hopefully escaping the fog.

Action(Rhogar): Ready to Bonk 1st hostile creature entering staff range.

Bonus Action(Rhogar): Bid Gorrah to Ready her stinger, same trigger.

End Turn(if above saves failed):
Gorrah's Wis Save(DC 15): 16. (And safe to presume the fear cause is not from a spell or magic effect, so no adv)
Rhogar's Wis Save(DC 15): 6.