The tentacled creature watched worrisomely struggle of the Nameless girl but once it was clear the corals are not about to release their victim, grinned as happily as her boss and attacked again:

vs Nameless Attack: 21 Damage: 26 thunder damage

Vadok abandoned his futile (and at the moment pointless too) attempts to free himself and finished the spell he was trying to use to save Hansel (Hasel got his 23 HP, waiting for 25 more from Trudie next round). He had that luxury because the mermaid, probably deeply insulted by Yusko's stubborn refusal to stay trapped, unleashed the power of her claws and the full weight of the rod on the monk:

vs Yusko: Attack: 23 Damage: 11
                  Attack: 14 Damage: 9

The rod missed Yusko completely, but the claw not only tried to slice his body but to restrain him as well (if the first attack hit, Yusko is grappled (escape DC 16))

Math (to check!)

 Map:

Yusko, Hansel, Davis! 

Davis gathers his strength, then attempts to free the person closest to him once again...

Athletics: 24

Also, the attack on Yusko needs to be rerolled if it hits. Davis will use his reaction.

Runic Shield
When another creature you can see within 60 ft. of you is hit by an attack roll, you can use your reaction to force the attacker to reroll the d20 and use the new roll.

Attack re-roll on Yusko: Attack: 25

(I wish I rolled like that for my characters attacks)

Davis finally did it - Trudie was free if a bit slowed down!

Yusko was not surprised when he got hit and a little annoyed when he got grabbed.  Laughing he said, "Don't worry Love, I'm not going anywhere."  He then proceeded to stab at her twice headbutt her in the face twice in rapid succession.

Grapple prevents movement but not attack

Attack 2 knife stabs, bonus action flurry for 2 unarmed attacks

Attack: 20 Damage: 8

Attack: 10 Damage: 8

Attack: 14 Damage: 8

Attack: 13 Damage: 6

(Math correction, Nameless one is at 53hps after that last hit.)

“My hero!” Trudie chimes to Davis. “Lookit me, a silly damsel in distress.” She adjusts her helmet, putting it back the right way. “Oh my.” Her eyes blink slowly as if coming to a realization. “An’ here I thought it was my arthritis acting up.” The old tortoise would shimmy, slowly, “How ‘bout some aleve...” and give her staff a little shake. It was worth a shot.

Casting Dispel Magic on Hansel
Movement to AE 10 ish?

I think Trudie has to finish her Cure Wounds spell first, before casting Dispel

And if that's the case, then Hansel will cast DIspel Magic on Trudie instead.

(Sorry, for some reason I thought it was my turn O.o My apologies. lol Way ahead of myself. Suppose that’ll be the next turn. *facepalm* )

(Np! Dispel speed: 8)

Yusko's opponent was slippery as an eel and not all strikes hit the target, but they kept her angry, that was probably the best thing at the moment. The mermaid hissed and tried to hit him once again with the rod:

vs Yusko: Attack: 31 Damage: 10

Hansel started to chant holy words of freedom directing them at Trudie but realized he has to be patient - it was as if he was talking through the water.

Round 7

Math

 Trudie was free but still felt slow and had to finish her healing spell, while Hansel's words began to sink in her mind, clearing it from unpleasant slowness.

Nameless One!

(Why?! WHY?!)

Ok, we roll with it. Adjusted math:

Nameless one growls at the rocks that hold her in their vice like grip. She decides to ignore it and fires a shot at the Mermaid who is now within her view. 

Attack: 15 Damage: 9

Attack: 22 Damage: 9

+3 sneak attack damage on the first one to hit, since she's in melee with an ally.

Dispite her troublesome position, Nameless girl managed to shoot the mermaid but the monstrosity had another target for the moment and instead of her, the tentacled creature, enjoying the play with her captive audience, decided to rectify the girl's ability to fight. Black as the night itself biting cloud of darkness covered them both.

Nameless and Yusko, take 9 poison damage or half as much on DC 14 Constitution saving throw. 

Not bothered by the effect mermaid attacked Yusko again, trying to press her claw deeper into his side and smacking with the heavy rod.

vs Yusko: Attack: 27 Damage: 7

                  Attack: 28 Damage: 10

Still slowly moving Vadok looked around with the said eyes and tried to invoke another incantation: 12 HP (14 )

Map

 Davis, Yousko, Hansel!  (the mermaid and the tentacled creature are in the magic darkness at the moment, as well as Yousko and Nameless)

Wow! A miracle happened - Vadok's determination overcame the horrible slow effect and everyone got healed on the spot.

Math, adjusted (poison effect is not included):

Con Save DC 14 : 5

Nameless is a 69hp.  

Davis uses his reaction to make the mermaid reroll the 29 to hit.

Davis then moves to Nameless and attempts to break them free...

Athletics: 14

Re-rolled attack: 15 (still hit, sadly)

(Lol! didn't figure it would make a miss, but it didn't even really make it even close to missing.)

(Forgot to make CON save at end of last turn against Slow: 3) (It is a CON save isn't it?)

Happy to see Trudie free of the spell, Hansel then tries to Dispel the magical slowness on himself...

(It certainly is the Con save with DC 18)

9 It felt as if water became even thicker around him. So much so, even words were caught in it and did not want to come out. Hansel began to say the prayer but even as he spoke, he knew it will take two rounds especially long to finish the chant.