Joetaro Wisdom - 23

He grits his teeth and aims at the priestess, casting Guiding Bolt at the witch

Attack: 14 Damage: 15

Sekkar Wis save: 12

Being a simple man of weapon, Sekkar just attacked a clear target right in front of him (and still restrained):

Bonus: [spell]Ensnaring Strike[spell] (Str13)  1

Attack: 24 Damage: 9

Attack: 26 Damage: 11 + 7

Not satisfied he tried to bite off priestess head: Attack: 17 Damage: 8

Kastix Wis Save: 11

"Argh! Just Burn!" Kastix shouts before casting Burning Hands at 2nd level, aimed the priestess and her followers.

Dex Save: 15

Damage: 17 Fire Damage. Half damage on successful save.

The circling demon spirits summoned by the daughter-priest wreck havok with the crowd and the combatants alike, striking both fear and pain. Joetaro avoids the worst of it, but responds by firing a bolt of divine power, but with the crush of the crowd his aim goes astray. Sekkar though is front and centre of the action, with an enemy locked down by a giant spectral lobster claw. He lashes out with the power of both arm and nature, striking two blows and biting a chunk of fishy flesh from her face, and leaving her entangled in thick dark vines that sprout from the earth below.

Meanwhile, Kaylyn notices that the kuo-toa wading in the shallows of the lake start crying out and flailing around. Several are pulled under the water, or are striking at unseen foes beneath the surface, and the water starts to foam red with blood.

Now even further imprisoned than before, Zeno stabs at Blopp from Sekkar's left, drawing blood from the priestess with a huge gash to her leg. Kastix releases his spell along with his exclamation, sending a sheet of flame at the defenseless priestess, which also burns those behind. One of those who came to the father-priests aid dies instantly in the flame, as well as two of the crowd beyond, and the panic turns into a rout with kuo-toa stampeding to escape. As the priestess falls beneath the flame, she cries out one last time to her god: Leemooggoogoon!

Meanwhile, Jimjar tries to contribute to the chaos by stabbing at the guard with the glowing head. His strikes are very efficient, and the guard screams in pain, causing the other nearby guards to freak out and flee. At the other end of the column, the duergar prisoner suddenly starts to grow in size, equaling and then passing Derendil in height as he shoves at the guard beside him, knocking him into the pit. Screams, flashes of light and lightning, evil spirits, blood, fire ... all combine in the crowd to create a sense of utter chaos, fear and dread.

And yet amid this mayhem, another sound rises above the burbling screams and cries of the kuo-toa. The dark surface of the water farther out bubbles and begins to foam. A thick, oily tentacle bursts froth, followed by another. Then two monstrous heads break the surface, both resembling hideous, angry baboons with wickedly curved tusks. Both heads are attached to a single torso, and the monster's red eyes burn with bloodlust and madness. The creature rising from the Darklake must stand thirty feet tall or more, with water cascading down its back and shoulders. Upon reaching its full height, the great demon throws back both its head and roars!

The cries go up louder than ever from the panicking kuo-toa LEEMOOGGOOGOON!! as the demon lord wades toward the shore...

Sekkar suspected something like this - a creature posing as a god. But he did not expect that! It seemed eliminating of the priestess was not enough after all...

Bonus action: Hunter's Mark on the monster

if this is the same combat:

Attack: 22 Damage: 7 + 6

If this counts as a new combat - additional attack:

Attack: 16 Damage: 14 + 2

"Screw this!" Kastix shouts looking up and up and up before casting Cure Wounds at 2nd level on himself and just try to hightail it out off the altar.

(It's 30ft tall right? We're a bunch of level 3's and that's beyond Gargantuan)

Healing 13

Oh, by the way, everyone please make a CHA saving throw. Witnessing the rise of the Prince of Demons from the Darklake is enough to drive just about anyone mad!

Kuo-toa are everywhere; running in frantic circles, laying down; some are screaming, some are laughing uncontrollably, some are weeping; many are just standing dumbfounded. The Enlarged duergar is running toward the docks. Jimjar has run into the crowd somewhere. Sarith is still near the altar, eyes wide open staring at the enormous demon, and babbling incoherently. Derendil is squatting on the ground staring at his feet and howling.

The demon is still 200 feet away, so definitely out of melee range. My apologies for the lack of relevant information. Kudos to Sekkar though, for having a swipe at frickin' demon lord!

Kastix Save: 22

Obviously, Sekkar is not that caught up in the battle to run towards the demon - he would attack only in desperation if the way is blocked.

CHA saving throw: 19

Zeno CHA save: 17

Zeno tries to stick close with the others and flee from the lake.

Religion check (do I know who/what this is?): 3 (nope.)

WIS Save: 8

CHA Save: 12

In the confusion Rhayna will try to get closer to Kaylyn.

(Sorry for the delay)

Joetaro CHS saving throw - 17

Wis saving throw 21

Con saving throw for concentration on Hex if Blopp is still alive 23

Cha saving throw 19

OK, thank goodness most of you made your saving throws. All except Rhayna, who is now afflicted with short-term madness for 9 minutes. I'm going to roll the random effect as per DMG: 23 "The character falls unconscious."

The sight of the demon is horrific to all, but Rhayna knows exactly what this creature is, her knowledge of it much more detailed than any present. Her studies in myriad tomes of demonic lore describe it perfectly, although at the time she could barely imagine such descriptions accurate. Now face-to-face with Demogorgon, the Prince of Demons, her knowledge of all its horrors overcomes her psyche, and she collapses unconscious on the ground.

Joetaro fights to remain standing as the crowds of kuo-toa run every which way. Some are making their frantic way toward the gates at either end of the village, but most are simply too crazed or afraid to think rationally. Meanwhile, Kaylyn, Kastix and Zeno have noticed some kuo-toa are fighting their way through to the docks and the several keelboats that are moored there, and the over-sized duergar is pushing his way past them toward the docks as well. It seems strange that anyone would choose to launch onto the lake right now, but then the duergar seems to be the most level-headed of all the crazed mob around here.

With the horror that has arisen from the lake Kaylyn barely noticed the pain she just felt from the guardians around Bloop.  

"Run!" She yells trying to get out of the village as quickly as possible.

Joetaro nods as he runs out of the village to follow Kaylyn.

To Sekkar water was the way to go from the start, not to mention hoards of mad fishfolk would more likely to attract demon's attention and seemed too chaotic to fight through to the gates. "To the docks!" yelled Sekkar, when Rhayna suddenly fell unconscious. Mumbling something untranslatable, he picked her up on the go (Stool, unlikely willing to leave her side too) and run after duegars, squinting on the boats to choose the one safest from the attacker.  

“What in the Nine...” 

Zeno stops mid-curse as he sees Rhayna collapse in front of him, then Sekkar is there to scoop her up and he begins running toward the docks.  Everything is Zeno’s brain says to run away from the water, but he takes precious seconds to fight the panic and study his surroundings.  Making a decision, he runs with Sekkar back to the docks, crying out to the others to follow.  He will help Sekkar with the myconid as well if he is struggling at all.

Kastix has long since taken to running, jumping or pushing everything in his way. 

Kaylyn quickly follows the others as they make their way to the docks.

"Boats!  If we can get boats then stay close to shore and move away from the village!"

Kaylyn has no issue blasting anyone in her way with her Eldritch Blast to help clear the way to the boats.