LAIR ACTION

As to prove that the ritual has already started to take hold, Gar thrusts his trident downward and screams: "Rise!"

Five undead sailors rise from their slumber and immediately show ill-intent towards Gar's enemies. (They go on initiative count 9.)

(Bubbles, Gulp, Shanty, and Undertow all go next.)

"What da ya know! It was him! And with a friend!" Gulp propelled himself to the newly introduced "faithful servant" and poked him with the dagger:

Attack 1: 18 Damage: 8

"Oh, sorry, I mean this" he extended his hand but instead of grabbing the servant's hand slapped the blue man a couple of times:

(If the first attack hit -  a Stunning Strike (the target is stunned until the end of your next turn if it fails a CON saving throw (DC 15).)

BA: Flurry of Blows:  Attack: 28 Damage: 10

                                     Attack: 16 Damage: 10

If Stunning Strike worked, then 2 more rolls for advantage from stun:  24 and 16

Plus second roll for Attack 2 (in spoilers)  with the dagger (if stun worked) 16 

(Sorry for the mess! Did not want to re-roll the whole post)

Shanty hisses in distaste at the sight of the undead, but focuses on the man summoning them.  Gar feels the water around him solidifying, and his limbs beginning to not function.

(Hold person, DC 15 Wis save)

Undertow may have had words for the slimeball messing with the dead. But in the heat of the moment, his focus was set on swimming closer, but at an off-angle for a better position, before relaying a set of commands in halfling. Soon after, Riptide is bursting forward and eventually behind Gar's new friend, allowing Undertow to fire with a little more confidence of success. But one way or another, Riptide is given a chance to join in on the fun in attacking Gar's ally as well.

Movement(Undertow): To AL-35.

Then, if both Gar and Scholar are within 5ft of a zombie:

Action(Riptide): Defensive Training.

Movement(Riptide): To AF-33. (avoiding entering melee with Zombies along the way, if possible)

Bonus Action: Cast (2nd level)Hail of Thorns.

Action(Undertow): Fire Handcrossbow, targeting Zombie within 5ft of both Shaolar and Gar.
#1 Shot - Attack: 8 Damage: 9 non-magical piercing.
#2 Binding Strike - Attack: 27 Damage: 11 magical bludgeoning damage(to Shaolar). If hit, target is also grappled.

(When target is hit by Shot, both target and each creature within 5ft of it must make Dex Save(DC 15) or take 4 magical piercing damage.)

OR, if no zombie is within 5ft of both Gar and Shaolar.

Bonus Action(Undertow): Command Riptide to move to AF-33, and attack Scholar.
Binding Strike - Attack: 11 Damage: 7 magical bludgeoning. If hit, target is also grappled.

Action(Undertow): Fire Handcrossbow, target Shaolar.
(Use above attack rolls for simplicity, but with the added cavaet of this.)

S/N:
1) If Gar is still at AG-33 by the time Undertow's turn rolls around, then  his 1st shot would be directed at Shaolar instead. Yes, that means if the attack hit and spell is triggered, whoever is in melee will be effected. Though, at that point it should only be Gulp, who has evasion, so he should be fine.
2) Riptide will move in after 1st attack to avoid getting caught up in any AoE, but still remain able to attack after. He will also if need be, and if 60ft of movement is enough, swim over head to get to the originally described destination.

DM's Screen:

(@Blue: I am not sure why the second attack is within a spoiler, but let me know if I am missing anything.)

Gulp rushes forward, making sure not to swim too close to any foe other than his intended one {AH-33}. Feigning diplomacy, the monk strikes at Gar's water genasi companion with both blade and fist. Although most of the strikes manage to bypass Shaolar's Mage Armor, he does not look stunned. (Shaolar takes 30 piercing and magical bludgeoning damage.)

DM's Screen:

Shanty sings a holding spell aimed at Gar himself! The spell begins to take hold but Gar shakes it off (Legendary Resistance used.)

"I won't be that easy!" Gar defies the bard. At the end of Shanty's turn, Gar uses a Legendary Action to quickly burst-swim to his companion's aid {AG-33}.

(OOC: DnDBeyond is acting a bit strangely at the moment, seemingly going offline and back online every few seconds. So, I'll pause today's update here. This gives @Ori a chance to revise their post if so desired given the resolved turns above. Also, we are still waiting for @MuggsHill to post Bubbles' turn.)

Amended post....

Seeing their prey again, but annnoyed that it is seemingly out of range to attack, Bubbles shoots forward (to AJ29) and hunkers down,  Last Rites raised high as he holds an attack should any of them approach, content to see the damage being done by the others., If attacked, he will respond Recklessly to inflict as much damage as he can, a flash of divine power accompanying the first strike that hits as he channels a small piece of divinity through the weapon.

Divine Fury 5 to be applied to the first

Last Rites attack 1: 29 Damage: 13

Last Rites attack 2: 26 Damage: 18

(@MuggsHill: Reckless Attack is a feature that only applies during your own turn, so I'm afraid you can't use it on a reaction. The exception is if using the reaction in your own turn.)

(OOC: I'm amending this post after some discussion in the OOC Chat.)

Already moving forward by the time his quarry swims away, Bubbles laments not being able to reach Gar right away. Despite reaching some of the undead Gar raised, Bubbles chooses to hold his attacks in case Gar decides to swim back toward him. Instead, Bubbles unleashes his fury against one of the recently risen undead. Two attacks and a flash of divine light force the undead sailor to burst into a dozen pieces. (Undead Sailor #2 takes 45 magical piercing and radiant damage and is DEFEATED.)

LEGENDARY ACTION

Gar thrusts Wave, his powerful trident, into Gulp's gut:

-> Wave vs. Gulp: Attack: 17 Damage: 7 

Gulp skillfully strafes away from the blow.

DM's Screen:

(@Ori: Your turn got a bit jumbled with the edit. I'm interpreting it as Undertow not casting Hail of Thorns at all. Let me know if I need to correct anything.)

Undertow communicates with Riptide in a language few are likely to understand in this situation. Both master and beast swim closer to the enemies and attack. Undertow's crossbow bolt assails Shoalar, and Riptide follows it up with a tentacle attack that grapples the water genasi. (Shaolar takes 17 piercing and magical bludgeoning damage.)

Gar Speaks loudly: "You are in my domain, and what is mine belongs to Umberlee! Taste of Unberlee's Wake!" Gar points to a spot just about where Amble is located. From there, the density of the water begins to increase, making it harder for the locathah and tortle to move. Riptide is the only ally far enough from this effect to not be bothered, and the undead sailors seem unaffected.

-> CON saving throw {DC 18} vs. Umberlee's Wake. Those who fail are basically under to effects described in the second paragraph of the Slow spell, excluding the penalty to AC and DEX saves. We'll call it Semi-Slow:

• Barnacle: 26
• Bubbles: 14
• Gulp: 16
• Sandlot: 18
• Shanty: 6
• Undertow: 3
• Amble: 24

Farther from the epicenter of Unberlee's Wake, Bubbles and Gulp are afforded an extra half-a-second to brace themselves. The effort yields dividends, and the barbarian and monk resist the powerful effect. Barnacle, Sandlot, Shanty, Undertow, and Amble all feel the waters about them become harder to navigate. What is worse, the effects seem to cling to each adventurer as opposed to be specific to the area.

(Sandlot and Barnacle are up next. Please keep in mind the effects of Semi-Slow. They can each repeat the CON saving throw {DC 18} at the end of their turns to try and escape this effect.)

"Hold fast... all... and know.... Lady Eldath... is with us." Sandlot proclaims in turn, holding his holy symbol high, and delivering the blessing onto those he could that seemed to be struggling the most. But even that simple effort alone leaves him breathless, and needing to dig deep for a few moments just to recover. In that time, Sandlot spreads a little further from the others, leery of the Gar having more in mind for the clustered up.

Movement: To AO-28.

Action: Grant Sandlot, Barnacle, Amble, and Shanty the benefits of Embolden Bond.

End Turn: Con Save(DC 18): 15.

Barnacle rushes headlong into the fray, or moves as far as he can towards the fray. At a reasonable pace. A sedate pace. A lovely afternoon stroll pace. Still, it's plenty of time to load, aim and fire a crossbow at Gar's new undead friends...

Attack: 7 Damage: 2 (plus 1d4 to attack roll from emboldened bond: 2)

Lowering his crossbow, he points towards Gulp, "Hey buddy, try doing the stabby stabby thing again!"

Using a superiority die and forgoing Barnacle's second attack for commander's strike. Gulp can make another attack against the mage (uses his reaction) and add 1d8 to the damage roll.

CON save: 12

Moving with difficulty, Sandlot holds up his music box and calls for another temporary divine bond to be formed between himself and a few of his allies. The old locathah can't help but feel a bit tired after 'all' that effort. He knows that it shouldn't feel this tiring.

-> Sandlot, Barnacle, Shanty, and Amble are now benefiting from Emboldened Bond

(@MB: Because of the effects of Semi-Slow (almost all of the second paragraph in the spell's description), you neither have a second attack nor a bonus action to spend to trigger Commander's Strike this turn.)

Barnacle takes a casual swim forward {AP-32} and shoots a pre-loaded crossbow bolt at the nearest undead sailor. The bolt comes to a complete stop as it travels through the water, never reaching its target.

Barnacle sees an opportunity to spur Gulp into another attack, but can't force the commanding words from his throat. Instead, the fighter focuses on fighting back whatever effect Gar placed on him. He succeeds in his attempt to regain control of his movements.

-> Barnacle is no longer affected by Semi-Slow.

Unable to move and a bit surprised that so many attacks have been directed at him by complete strangers, Shaolar lifts a finger and aims it at Gulp. Without saying a word except for some brief incantation in Aquan, the genasi launches a Lightning Bolt at the monk, making sure to also catch Undertow in the line of attack.

-> DEX saving throw {DC 15} vs. Lightning Bolt Damage: 32

• Gulp: 19
• Undertow: 23

The monk and the ranger prove to be quite nimble. Despite the point-blank attack, Gulp completely avoids it (Evasion). However, Undertow can't dodge all of the lighting arcs. (Undertow takes 13 lightning damage.) 

Amble waves at Sandlot, thanking him for Eldath's blessed bond. They repay the cleric in kind by invoking that calming green light into the piece of cloth that hangs from the tortle's neck and expelling the effects of Umberlee's Wake from the locathah.

-> Amble casts Dispel Magic on Sandlot, doing away with Semi-Slow.

The tortle then attempts to regain control over their own body, albeit through a more physical effort. They succeed.

-> Amble's end-of-turn CON saving throw {DC 18}: 28

DM's Screen:

The undead sailors go next, an they mindlessly surround Bubbles. There are four of them and they each attack twice with advantage due to Reckless Attack.

-> Rusted Longsword vs. Bubbles: Attack: 14 Damage: 9 (I mistyped the attack roll and need to add another +4 to it. The total is 24.)

-> Bubbles' CON saving throw {DC 12}: 9 

-> Rusted Longsword vs. Bubbles: Attack: 22 Damage: 5

-> Bubbles' CON saving throw {DC 12}: 23 

-> Rusted Longsword vs. Bubbles: Attack: 12 Damage: 11 

-> Bubbles' CON saving throw {DC 12}: 15 

-> Rusted Longsword vs. Bubbles: Attack: 16 Damage: 10 

-> Bubbles' CON saving throw {DC 12}: 23 

-> Rusted Longsword vs. Bubbles: Attack: 19 Damage: 5 

-> Bubbles' CON saving throw {DC 12}: 18 

-> Rusted Longsword vs. Bubbles: Attack: 20 Damage: 10 

-> Rusted Longsword vs. Bubbles: Attack: 22 Damage: 9  

-> Rusted Longsword vs. Bubbles: Attack: 21 Damage: 8 

Bubbles is assailed by a storm of rusty blades, earning a new wound with each slice. One of the cuts feels warmer than the others, though Bubbles feels nothing other than that for now. (Bubbles takes 31 slashing damage, already halved.)

(@MuggsHill: Let me know if you want to use Fanatical Focus on that failed CON save. If so, please note that you'd have to roll two more saves for the last two attacks since they also hit.)

END OF INITIATIVE ROUND 1

THE FINAL COUNTDOWN - Initiative Round 2

• 20. Lair  
• 18. Bubbles (70/101; orange) - Rage (9),
  
• 14. Gulp (75/76; pink) -
• 14. Shanty (67/67; blue) - Semi-Slow, Emboldened Bond (d4);  
• 13. Undertow & Riptide (78/91 & 65/65; green) - Semi-Slow;
• 13. Gar Shatterkeel (black) -
• 12. Sandlot (75/75; cyan) - Emboldened Bond (d4), concentrating on Control Water;
• 11. Barnacle (76/104; red) - Emboldened Bond (d4);
• 11. Shaolar Quanderil (gray) - grappled, Mage Armor;
• 10. Amble (90/90; lime) - Emboldened Bond (d4);
• 09. Undead Sailors (x4) -

MAP:

NOTES: ---

(LAIR goes next.)

LAIR ACTION

A arm of coral sprouts from the nearby coral mound and engulfs Gar. He makes sure to lay a hand on Shaolar as well, so that the rapid growing coral engulfs the water genasi too. Then, the humanoid-shaped coral pieces break away in a million particles and the two enemies are nowhere to be seen.

A moment later, they both sprout out of another patch of coral clinging to the shipwreck to the northwest. It seems the ability to teleport through the coral is not restricted to only Gar.

-> Gar is now in square {AA-19} and Shaolar is right next to him in square {AA-18}.

(Bubbles, Gulp, Shanty, and Undertow are up next. Shanty and Undertow should keep in mind the effects of Semi-Slow, but they can each repeat the CON saving throw {DC 18} at the end of their turns to try and escape this effect.)

OOC: Bubbles will save his reroll for another time...with nothing immediately affecting him he will shrug it off.

Facing off against the mass of attackers Bubbles begins to revel in the feeling and loses himself to the fight, attacking recklessly, imagining himself as Whirlpool, and hitting as hard as he can using the GWM feat to boost damage, targeting a single ceature until it goes down, then moving on.

Divine Fury 8 to be applied to the first attack that hits

Last Rites attack 1: 20 Damage: 27

Last Rites attack 2: 23 Damage: 27

Given he finished one off last round below is the extra roll if he kills one or scores a critical

Last Rites attack 2: 19 Damage: Unable to parse dice roll.