Hilke waits as Dav'eed moves through the underwater passage.  She keeps one of her javelins in hand, trying to keep a sharp eye out for any danger.  Seeing Zelaerys trying to communicate, she watches him as well to see what information he gets from the half-elf. 

The rogue surfaces slowly, barely causing a ripple as his eyes and nose emerge above the surface of the water. He stays against the far rock wall to be as hidden as possible, and he whispers back what he sees to Zelaerys. "Kobold shaman chanting - several females holding eggs. Swim is easy - 30 seconds. Come now - surface quietly!"

(I remember that Dav'eed left his armor, rapier, bow and arrows behind, which is fine. He'll do his roguey thing with the dagger if it comes to that!)

Zelaerys listens intently to the rogue's whispered report, his deep blue eyes reflecting the seriousness of the situation. He turns to his two companions, his voice low and steady as he relays the message. He quickly distributes Dav'eed's armor and weapons among the group, ensuring that everyone carries a manageable load. He hands a piece to each companion, careful not to overburden anyone. "Here, take these," he says, passing the armour to Hilke and a rapier to the Huttmoff. "I'll carry the remaining pieces. We need to be swift and silent." Before they set off, Zelaerys places a hand on each companion's shoulder, offering a brief but heartfelt blessing. "Yondalla, grant us your divine guidance. Keep our movements swift and silent, and protect us as we navigate these waters. Bless us with your light and lead us to success." With the blessings given, Zelaerys nods to his companions, signaling for them to proceed. He watches as they enter the water, ensuring they move quietly and efficiently. Once they are all in, he takes a deep breath, utters a final silent prayer to Yondalla, and follows them into the water, his movements careful and deliberate to maintain silence. One after the other, they swim towards their objective, united in purpose and strengthened by his faith. 

If needed a stealth skill check:

(I think it would be too much of a stretch to assume that everyone can pass one after the other with guidance for stealth but I thought I put it here for atmosphere anyway without a mechanical advantage.)

Hilke takes the armor and proceeds to make the swim through the passage.  

(Stealth if needed: 3)

The four of you make your way through the under water passage with ease. Zalaerys nearly explodes with a quick breath upon surfacing but manages to contain himself. Your Eyes just peeking out of the surface of the water. The cavern is dark with only the dancing flickers of a large fire in the short distance to illuminate the vast reaches. A group of Reptilian men and woman dance frantically about the fire. One of them, a large male with a feathered headdress leading the procession of quick gestures and guttural chanting.

The group is intent on their own doings, the females of the group caressing and holding aloft the leathery eggs of their offering. The eggs shift and twist of their own accord, the creatures inside stretching and prying against the tough leather exterior. The group is so engrossed in the ritual, none of them have noticed your heads surface.

Hilke, when she surfaces, takes a quick look around, trying to determine if there are any other exits from this chamber. (Perception: 16)

Huttmoff was the last one to enter the water, feeling uneasy at best going completely under. He is used to high mountains, rushing rivers, but this dark, stank, underground water in claustrophobic caves really stresses him out. He also casts his eyes around the cave, trying to protect the rear, before finally diving in himself. 

Huttmoff would do his best to be the last one to come out of the water, waiting for the rogue to make the first move. However, once he emerges, he ponders the ceremony he is watching, seeing if he recognizes any elements of the religious significance. Religion: 11.

(For future times, Huttmoff also have Guidance, so we can do at least two of us every time.)

It looks like my previous post didn't actually do the dice roll for some reason. If that stays the same, here is a backup roll: 8

Zelaerys whispers to Huttmoff, "You think they go through a ceremony or ritual?" and discusses various possibilities that occurs to them both in way of helping Huttmoff to find an explanation for what they witness.

Dav'eed gratefully accepts his armor and gear, submerging quietly to put the armor back on if he can. The bowstring will need to be replaced, but everything else will survive the immersion with a little care later on!

"I think they're trying to get the eggs to hatch. I'm not one to kill babies, or innocents, but I don't speak troglodyte so I can't negotiate with them. So...do we attack? Or just threaten and negotiate? Either way, we should swim over to the dry area to the south there..."

Your group hang in the water near the entrance, the only way in and out of this cavern, at least nothing else is obvious. Dav'eed resurfaces, his armor mostly in place (-1 AC for donning underwater). Keeping to the wall you swim slowly towards the far side of the room. The ritual is well underway, the forms growing within the eggs held aloft by the females. 

A tingle begins to fill the air, a swirl of hot air and gas coalesces above the flames of the fire. Demonic faces form within the swirling chaos, horrific beings are pulled from elsewhere. Pushing and stretching in the gas, pushing against the edges like a thin veil of cloth pulled over a shroud. As you reach the dry land one of the spirits stretches the thin membrane of smoke, it swirls quickly through the air, zipping about as a streamer of smoke before finding a leathery egg, it touches the leathery surface. It enters the egg, a thin stream being sucked into the Troglodyte within.

The shaman reacts by raising his voice in exultation, the ritual is reaching a crescendo. Huttmoff whispers, "I think he is infusing the eggs with demonic souls, if I am right they will not simply be Troglodyte children, they will be something much worse"

You have moved to the edge of the water and dry land. Not risking the noise of climbing out you hang low in the water watching the ritual unfold.

Hilke watches what now seems surely a demonic ritual. "We have to stop this," she whispers to the others.  She reaches to grab one of her javelins. "We should strike now before we have a whole collection of demon possessed trogs." 

Zelaerys takes a moment to offer a prayer, "Yondalla, guide my hand and give me the strength to protect those who cannot protect themselves.", He agrees that destroying the hatchery is the best course of action to prevent future harm to the townsfolk. "Though it pains me, I know this is the only way to ensure the safety of the townsfolk. We must destroy the hatchery to prevent further evil from preying upon our people." With a heavy heart but resolute in his duty, he readies a Fire Bolt to be launched at the Shaman, who seems to conduct the ritual, as soon as Hilke throws her javelin.

"Agreed," Dav'eed whispers. "Ain't killin' babies no more - this is stopping an evil plan before it hatches, so to speak. We all attack as one, focusing on the shaman and then any demon-infused eggs. Ready?"

When all nod or give a sign that they are ready, he gets ready to pull himself out of the water and attack. The rogue holds up three fingers, then lowers them one at a time in a silent countdown. At zero, he launches himself out of the water, rolls to a standing position, and readies himself to lead (or follow) his companions into a fray!

(In post 292 there was a scale. I would estimate that the shaman is between 90 to 120 feet away from the center of our group.)

Huttmoff recognizes how terrible he is at sneaking up (with his hulking frame and loud armor), so he remains in the shallow water until the fight has begun, as to not ruin any element of surprise. In the meantime, he begins to ready himself to cast Guiding Bolt as soon as one of his other party members attacks. His primary target would absolutely be the shaman, but if the initial attacks have already down the shaman, he would logically go to the next largest enemy.

Huttmoff is focused entirely on interrupting the successful completion of this ritual, but he still wants to follow the lead of his party, trying to take advantage of surprise as much as possible. 

As Dav'eed counts down, Hilke readies her attack, launching the javelin at the the shaman when it reaches zero. 

(Javelin Attack: 20, Damage: 3; assuming Disasvantage for range + Advantage for surprise - cancels out)

(Initiative: 13)

As Hilke hurls her javelin, Zelaerys releases the Fire Bolt at the shaman.

(Hit 13, 19 if with advantage, for 7 fire damage; Initiative: 1)

(If we're out of melee range - which is better for Dav'eed! - he will attack with his bow instead!

The Shaman continues the ritual, the faces forming, screaming from behind the thin veil between worlds. The group slowly circling the smokey fire. Another head stretches out, pulling a trail of smoke behind it. The first egg affected rends with the sound of thick leather splitting and tearing. The female troglodyte screams, dropping the egg before her.

Unwilling to wait any longer, Dav'eed flashes a quick countdown, charging from the water. A flash of fire roars out from behind him to splash against the Shaman, a javelin tears at the shamans arm. Surprised by the onslaught, the ritual ends with a cacophony of sound. Air rushes into the flames, the wind swirls in a great gust towards the fire. Erupting in a bright flash of light illuminating the entire cavern for a brief second.

A bolt of light strikes the Shaman, he staggers as motes of twinkling light make him an easy target for Dav'eed. The Shaman, badly hurt and quickly flagging from the brutal rush tries to gather his will, his strength.

The dropped egg erupts in viscous fluids, a small form suddenly spikes outward, one, two, thrusting legs, quickly growing longer. The beast snaps as bones crack and grow, flesh rends as it expands larger. Within seconds a Fiendish Troglodyte erupts from the leathery egg. Standing head and shoulders above the female, the beasts scales are smaller, tighter, hued with an infernal reddish tinge. It swings its head, eyes blazing with internal fires. Teeth as knives drip with a vaporous ichor, claws longer than your fingers twitch.

The fire dies, the smoke pulling apart into streamers, a half dozen screaming demonic faces hurl about the room, ricocheting off the walls before fading into nothing but vapors.

Hope the scale works better. The distance from center to Shaman was about 40-45'. Only Dav'eed moved during the surprise round.

Dav'eed please roll for Stench: Any creature other than a troglodyte that starts its turn within 5 feet of the troglodyte must succeed on a DC 12 Constitution saving throw or be poisoned until the start of the creature’s next turn.

Initiative

1. Surprise round...
2. Your party<---Your turn any order
3. The shaman is badly hurt and staggering backward
4. The Fiendish trog has fixed its gaze on Dav'eed
5. The female trogs?