Shipwrecked in Saltmarsh

Katernin may still act, but let's go to the ...
~Top of the Round~
Everyone may act.

Kelnan disappears into a silvery mist, hefting the box with him. Athletics: 3

He falls clumsily prone into the boat, dropping the box painfully on the Dwarven first mate's foot.

Everyone else may act. (Everyone can make it to the boat in a normal move without dashing except Dain, who can get there in a dash and a potential opportunity attack. The others may take an action as well. Of course, Dain may also fight and wait until a later turn to board the skiff. )

With Kelnan and the box disappearing, Molo turns back to Dain. Seeing some monstrosity following him, he shouts “Oh my god, that thing is so ugly it can only be a cursed hemorrhoid! Dain, swim faster, before it bursts!” 

for simultaneous inspiration for Dain and vicious mockery for the monster attacking him 

DC 14 Wis save for 1 psychic damage and disadvantage on attacks

Fianna

     Fianna swims her movement towards the skiff and sends one Eldritch Blast back at the monster…

Eldritch Blast Attack: 16 Damage: 13

Dain

     Dain, seeing the box got yo the skiff safely and all are in reach of the skiff, turns and swings his mail at the beast, wanting this thing dead rather than endangering the boat.

Attack: 10 Damage: 13  Plus 7 Radiant Damage from Divine Fury if he hits…

     No movement, no need to bring it closer to boat…

The demon contemplates Molo's magically-laced insult - DC 14 WIS save: 18 -
- but doesn't seem to fully grasp its intent. But it gives Dain a moment of humor and a boost of energy (bardic inspiration).

Fianna blasts it with a direct hit of potent purple plasma. The fiend shrieks and falls limp in the swells, quite dead. 

The skiff finally arrives. Everyone climbs in, Dain the last aboard.

No enemies remain visible, unless you count the massive tentacles which continue to smash the sinking ship into splinters.

"What IS that thing??" asks an out-of-breath Oskar, the first mate who is one of the two dwarven crew of the skiff. You watch as the Emperor of the Waves sinks entirely below the surface.

Molo starts trying to find an oar to get the skiff moving faster. “I don’t know, flee! Go, go, go!”

     “Impolite and quite violent,” Fianna adds.  “Thanks for picking us up, perhaps we should go far far away from the tentacles now though?”

     Other than being a smart Alec Gianna concentrates on using Prestidigitation to warm and clean herself and her comrades.  She figures the dwarves can run the boat better without her help so she does what she can to make the others more comfortable…

     She’ll also summon Fi’Finella back to her, having the Imp invisibly fly back to the ship so it can give a scouting report on the tentacles and demons - like if there’s any attempt to follow or such.

Dain just rests…

The party is bone cold after their abrupt swim in the early winter seas. Fianna's magical warming is quite welcome. The dwarves change the direction of the skiff, and head back to the ship. There's nothing left of the Emperor except a slick of oil and a debris field. The tentacles have submerged together with the old wreck.

Fi'Finella reports no sign of anything living - just Krell's floating body and dead spiders of all sizes.

Just as you are about to relax a little, the blue spider - the size of a polar bear - appears suddenly in the skiff. Stealth: 22
The small boat tilts precariously with the sudden weight.

Everyone is surprised. The massive creature lands on Molo. (Roll a DC 6 strength or dex save or be grappled and prone.) 

It takes a huge snap at Fianna. 
Bite Attack: 21 Hit: 9 piercing damage, and Fianna must make a DC 11 CON save, taking 21 poison damage on a failed save, or half as much on a success.

Initiative:
Fianna (if she's up): 9 
Katernin:  5
Kelnan:  12
Molo:  15
Dain:  5
Fi'Finella:  13 
Giant blue teleporting spider:  17 
Dwarven sailors:  12 

(After Fianna rolls her save, the spider will get a second chomp, then everyone may act.) 

One constraint: the boat is crowded. All melee and ranged weapon attacks will be at disadvantage. (Non-ranged spell attacks which aren't wielded like a weapon are not at disadvantage.)

Con save or no, Fianna is down.  Not enough damage to outright kill her if she fails, but enough to put her at 0 even if she makes.  ((I knew I shoulda healed instead of warmed!))

6 - decided to roll for funsies anyway…

failed! *sob*

The spider turns on the dwarven first mate, next. 
Bite Attack vs Oskar: 23  Hit: 6 piercing damage.
DC11 Con Save vs. 15 poison damage: 17
 The sturdy first mate suffers a nasty bite, but his dwarven constitution is well-suited to dealing with such poisons. He is seriously wounded but still standing.

Everyone except Fianna may act.

Reminders:
- Due to crowding, all melee and ranged weapon attacks will be at disadvantage. (Non-ranged spell attacks which aren't wielded like a weapon are not at disadvantage.)
- Molo: Roll a DC 6 Strength or Dex save or be grappled and prone, first

Molo DC 6 Dex save 21 

molo squirms out from beneath the spider, and lashes out with his scimitar (pack tactics make it a straight roll) 

Attack: 15 Damage: 6 

Kelnan

Panting and exhausted, Kelnan pulls himself up and tries to hit the spider with a Ray of Frost

Attack: 21 Damage: 7

Molo gives the massive spider a nasty gash with his scimitar.

The dwarves also pull out their blades and attempt a close-quarters attack on the thing:
Oskar: Blade attack vs Spider: 7. Hit: 2 piercing damage.
Dwarf sailor #2: Blade attack vs Spider: 11. Hit: 6 piercing damage.

Oskar manages to sink his blade into the belly of this enormous and wounded beast, but it fails to stop it.

Kelnan, Dain, and Katernin may act; Fianna may make her death save (unless Kelnan can stabilize or heal her; Katernin comes afterward in initiative.)

Reminder:
- Due to crowding, all melee and ranged weapon attacks will be at disadvantage. (Non-ranged spell attacks which aren't wielded like a weapon are not at disadvantage.)

Kelnan manages to freeze three of its spindly legs and part of its side. It's heavily injured.

Dain and Katernin may act; Fianna may make her death save.

Reminder: Due to crowding, all melee and ranged weapon attacks will be at disadvantage. (Non-ranged spell attacks which aren't wielded like a weapon are not at disadvantage.)

8
Death save #1

not to be shown up by his fellow dwarves, Dain grabs his mail and rushes forward to attack!

Attack: 24 Damage: 5

(...and a second attack roll due to disadvantage: 10 )

Katernin reaches out to Fianna to spare her from fading. "Please, not today," she whispers as she does so."

Action: Cast Spare the Dying On Fianna

Crowded a little too closely by his comrades, Dain flubs the swing of his maul. It barely brushes the spider's blue hide and nearly cracks the skiff's wooden seat.

Katernin stabilizes Fianna. She is unconscious as well as poisoned, but at least more comfortable and out of danger of immediate death.

The spider turns and takes a snap at Kelnan.
Bite Attack: 6   Hit: 7 piercing damage, and Kelnan must make a DC 11 CON save, taking 22 poison damage on a failed save, or half as much on a success.

 Kelnan ducks the nasty bite with a lucky dodge.

With a sudden lurch, the spider vanishes. *Blip.* The skiff suddenly rights, and Oskar is nearly thrown overboard from the sudden shift in weight.

Everyone may act, although there is no visible target.

Molo reaches to Fianna and grabs her by the neck. “Everything is going to hell! Wake up-wake up-wake up!” Practically throttling her as magic moves through his hands and into her. 

cure wounds 9 

Fianna is awake, but poisoned and completely paralyzed.

The spider is still absent.

The dwarves begin to row with urgency again, toward their ship.

Does anyone else want to act?