Focused on the blue man and raising his shield in defensive stand he din't notice the guards catched up. The first bolt passes from behind him almost hitting his head in a panic he raises a blue [spell] shield [/shield] just in time to block the rest of the arrows in his back.
Reaction: [spell] shield [/shield] +5 ac until start of Nox next turn (26 ac total)
However the Mual slams through both defenses hitting Nox on the siderib. The cat man is agony but still (barely) standing. (4 hp left :O)

Quote from Lerus17 >>

As best as it can, the Owl lets its master mentally know that it has located Dredge. (Never mind, the familiar is beyond the telepathy range of the Find Familiar spell.

 Lol, oh well the tabaxi screaming into the void telepathically. :P
The Owl tries to warn him a Fire Elemental coming Nox way but realise it to far from it master (the Owl doesn't know it Dredge). Seeing Grixx and Bone The Owl tries to get there attention and leading them back down to Nox. The Owl arrive at the same time as them.

At the end of the round Nox sees an Fire Elemental appearing. Not knowing it an ally "I ques i will spend 1 of my 9 lives today".

The Tall Blueman is now furious with the tabaxi in front of him who is full of tricks. It brings down it's maul once again:

-> Maul (melee weapon attack with reach) vs. Nox: Attack: 21 Damage: 39 magical bludgeoning.

He screams: "I WILL BRING YOU DOWN YET, CAT!"

(Nox and Dredge are up next.)

Nox both AC bonuses drops "In your dreams!"

Action: Nox keep poking the blue man with his rapier.

Attack: 20 damage: 16 piercing
Attack: 27 damage: 14 piercing
If hits Defensive flourish activates: 4 +damage, +AC until start of Nox next turn (used another bardic inspiration dice). (23 AC total if it succeed)

BA: misty step 30 feet upwards the stairs.
Movement: Running 35 more feet upstairs. (15 normal + 5 bard blade flourish + 15 feline agility)

NOX'S TURN

Nox attacks, defends, teleports, and runs up the steps. One of his stabs manages to nick his adversary (Tall Blueman - CMD: 34).

NOTE: I have adjusted the cumulative damage taken by the Tall Blueman after noticing that Nox's rapier attacks are not magical.

Nox then opens a 50 feet gap between him and the Tall Blueman (this accounts for the enemy's Huge size).

The Owl will turn around after reaching Bone and Grixx and accompany them back to Nox's location.

LEGENDARY ACTION (end of Nox's Turn)

The Tall Blueman produces a lightning bolt on his hands and launches it at Nox:

-> Bolt (ranged spell attack) vs Nox: Attack: 19 Damage: 35 lightning.

The lightning bolt flies by Nox, hitting the already precarious wall surrounding him.

REST OF THE PARTY

Le'gal casts Freedom of Movement on Talon to compensate for his stubby legs. Assuming that the bugbear has no need to purposefully run at less than full speed to keep up with Talon, Le'gal picks up his pace a bit.

UPDATED ETAs:

(Dredge is still up. He is now only 35 feet away from Nox.)

As Nox comes running up the stairs, Dredge comes charging down. He twists his form around the pummeled bard on the stairs and dashes straight into Big Blue, who takes 9 fire damage as the elemental fire surrounds his body. Blue Boy is also set aflame, and will take 3 fire damage at the beginning of his turn

DREDGE'S TURN

Dredge comes down the steps as fast as a wildfire, slamming into the Tall Blueman, who is set aflame and singes a bit (Tall Blueman - CMD: 38). The enemy acknowledges the arrival of the new opponent: "So at least one of your friends comes to your rescue, cat man!"

LEGENDARY ACTION (end of Dredge's turn)

"You'll not escape!"

The Tall Blueman produces a lightning bolt on his hands and launches it at Nox:

-> Bolt (ranged spell attack) vs Nox: Attack: 17 Damage: 29 lightning.

-> This should force Nox into being unconscious, incapacitated, and prone.

-> Hexblade's Curse on the Tall Blueman is dropped.

ARMORED GUARD (first batch)

The Armored Guards will advance further, stepping into difficult terrain. The next salvo of bolts attempts to pelt the prone but [condition]unconscious[/condition ] tabaxi:

-> Crossbow, hand (ranged weapon attack) vs. Nox: Attack: 8 Damage: 5 piercing.

-> Crossbow, hand (ranged weapon attack) vs. Nox: Attack: 18 Damage: 8 piercing.

-> Crossbow, hand (ranged weapon attack) vs. Nox: Attack: 8 Damage: 5 piercing.

-> Crossbow, hand (ranged weapon attack) vs. Nox: Attack: 14 Damage: 6 piercing.

(@Palfatreos: I find it hard to believe Nox would be able to keep up his defensive stance from Defensive Flourish after dropping to zero HP. I'll let it slide this time but you'd have to agree with me, right?)

They all miss.

LEGENDARY ACTION (end of Armored Guards#1-4's turn)

"Die, prey!"

-> Bolt (ranged spell attack) vs Nox: Attack: 28 Damage: 26 lightning.

-> This counts as a failed DEATH saving throw for Nox (successes: 0, failures: 1).

ARMORED GUARD (second batch)

Only 5 feet behind their colleagues, the next batch of Armored Guards lets loose another salvo of bolts:

-> Crossbow, hand (ranged weapon attack) vs. Nox: Attack: 12 Damage: 3 piercing.

-> Crossbow, hand (ranged weapon attack) vs. Nox: Attack: 6 Damage: 6 piercing.

-> Crossbow, hand (ranged weapon attack) vs. Nox: Attack: 9 Damage: 5 piercing.

-> Crossbow, hand (ranged weapon attack) vs. Nox: Attack: 6 Damage: 8 piercing.

They all also miss.

-> Here is a concentration save for the Blueman's Earthquake from Dredge's damage {DC 10}: 29 - spell is maintained.

END OF INITIATIVE ROUND 5

INITIATIVE ROUND 6

• 30. Collapsing Tower
• 19. Tall Blueman (CMD: 4; 0ft) - concentration on Earthquake (counter: 7), is set aflame for 1d10 damage each turn;
• 19. Nox (+50ft) - benefiting from +4 to AC until beginning of his turn, unconscious, incapacitated, prone, DEATH saving throws (successes: 0, failures: 1);
• 16. Dredge (0ft) - activated Rage (counter: 8); in the form of a Fire Elemental;
• 08. Armored Guards#1-4 (CMD: 0, -5ft); 
• 04. Armored Guards#5-8 (CMD: 0, -10ft). 

NOTE: I have switched the distances above to be relative to the Tall Blueman from now on. Current positions with the (+/-) indicate that you are (ahead/behind) him.

The continued Earthquake has at this point completely compromised the tower. At the beginning of each round, everyone must succeed a DEX saving throw or take bludgeoning damage (half-damage on a successful save). The DC for this save will get higher with each passing turn, as will the damage. If you all stay here for too long, it may get to the point where the damage is simply too much to bear (i.e. no more dice rolls, just a classic "rocks fall, you get crushed" event).

(Tower and Blueman will go next.)

Chunks of the tower begin to fall on everyone:

-> DEX saving throw to mitigate the damage of failing tower {DC 10}. Damage roll: 4.

• Bone: 22 - takes 4 bludgeoning damage.
• Dredge as Fire Elemental: 22 - takes 2 bludgeoning damage (already halved for elemental-ness).
• Grixx: 10 - takes 2 bludgeoning damage (already halved for barbarian-ness).
• Le'gal: 9 - takes 4 bludgeoning damage.
• Nox: auto-fails DEX saving throws (unconscious) - counts as a DEATH saving throw failure (successes: 0, failures: 2).
• Owl: 7 - takes 4 bludgeoning damage - the familiar disappear in a puff of arcane incense dust and smoke.
• Talon: 19 - takes 9 bludgeoning damage.
• Tall Blueman: : 13 - immune to non-magical bludgeoning damage (CMD: 4).
• Armored Guards#1-4: 18, 6, 11, 9 - two take 4 bludgeoning damage, two others take 9 bludgeoning damage (CMD#1: 9, CMD#2: 4, CMD#3: 9, CMD#4: 4).
• Armored Guards#5-8: 9, 14, 17, 11 -  three take 4 bludgeoning damage, another take 9 bludgeoning damage (CMD#5: 9, CMD#6: 4, CMD#7: 4, CMD#8: 4).

The Tall Blueman begins his turn by taking 3 fire damage (Tall Blueman - CMD: 7). He then flies up 5 more feet up such that Dredge and him are not occupying the same space. As mentioned earlier, the ceiling is 25 feet high, so there is just enough space for the Huge-sized Blueman and the Fire Elemental to not be vertically in the same space.

He will then switch target: "Another prey for me to hunt!"

-> Maul (melee weapon attack with reach) vs. Flame-Dredge: Attack: 19 Damage: 31 magical bludgeoning (not yet halved to account for Rage).

-> Concentration save on that Earthquake {DC 10}: 14 - the rumbles continue on.

-> Dredge's CON saving throw {DC 15}: 15 - nothing happens.

(Flame-Dredge is up next, and Nox needs to roll a DEATH saving throw.)

Talon stops.  Realizing that if they don't figure out how to get out of this place soon they will all die.  "Le'gal, bring the sarcophagus over here.  It there are many items of value inside.  I think we can make a sacrifice that might create power in this clockwork item we have."  He pulls out the device and begins to think hard about the items in the sarcophagus that could be used to help this device work.  "Do you have any way to do an Investigation on how to make this work.  I feel you are more skilled than I in this matter."

Seeing the tower about to crumble, Dredge continues dashing down the stairs with a faint “maybe next time, Big Blue!” He runs through the armored guards as he goes, causing them to each take 1d10 fire damage and setting them alight.

For reference (becasue the amount of AoOs I’m about to take is going to be insane), AC of 17 (opting to use the Unarmored Defense feature using the Fire Elemental stat block instead of the AC of the Fire Elemental) and rage persists because of the swipe from Blue Boy

Nox death save roll: 2 Nox puff out existance just like his famialiar/mount.

NOX'S TURN

The damage from the falling piece of wall reopens any wounds that might had begun the process of closing. Nox bleeds out and begins to fade away.

LEGENDARY ACTION (end of Nox's turn)

Tall Blueman swings at Dredge once again:

-> Maul (melee weapon attack with reach) vs. Flame-Dredge: Attack: 36 Damage: 36 magical bludgeoning (not yet halved to account for Rage).

-> Dredge's CON saving throw {DC 15}: 22 - nothing happens.

DREDGE'S TURN

Seeing Nox expire, Flame-Dredge turns and runs down the steps, making sure to set all opponents aflame on his way (i.e. not moving in a straight line.) Each Armored Guard takes 8 fire damage. (Armored Guards#1-8 - CMDs in order: 17, 12, 17, 12, 17, 12, 12, 12).

Flame-Dredge exposes his back to a slew of attacks while running the gauntlet (NOTE: Damage rolls below have already been halved to account for resistances):

-> Maul (melee weapon attack of opportunity with reach) vs. Flame-Dredge: Attack: 23 Damage: 16.5 magical bludgeoning.

-> Dredge's CON saving throw {DC 15}: 27 - nothing happens.

-> Slam (melee weapon attack of opportunity) vs. Flame-Dredge: Attack: 24 Damage: 3 bludgeoning.

-> Slam (melee weapon attack of opportunity) vs. Flame-Dredge: Attack: 10 Damage: 3 bludgeoning.

-> Slam (melee weapon attack of opportunity) vs. Flame-Dredge: Attack: 14 Damage: 2.5 bludgeoning.

-> Slam (melee weapon attack of opportunity) vs. Flame-Dredge: Attack: 17 Damage: 3.5 bludgeoning.

-> Slam (melee weapon attack of opportunity) vs. Flame-Dredge: Attack: 10 Damage: 4 bludgeoning.

-> Slam (melee weapon attack of opportunity) vs. Flame-Dredge: Attack: 11 Damage: 1.5 bludgeoning.

-> Slam (melee weapon attack of opportunity) vs. Flame-Dredge: Attack: 5 Damage: 1.5 bludgeoning.

-> Slam (melee weapon attack of opportunity) vs. Flame-Dredge: Attack: 22 Damage: 3 bludgeoning.

(@Hydra: As of the end of your turn, you'd need 4 full turns of dashing, so 100 feet of movement per turn, to reach the base of the tower. That is how long it took Nox to get up here with approximately 90 feet per turn. Also, please note that your Fire Elemental's AC is 16, as the creature has a DEX of +3 and a CON of +3.)

LEGENDARY ACTION (end of Dredge's turn)

The Tall Blueman produces a bolt made out of pure coldness in his hands, and launches it:  "Another runner... Another hunt!"

-> Bolt (ranged spell attack) vs Flame-Dredge: Attack: 26 Damage: 12.5 cold (already halved).

(Another post incoming.)

ARMORED GUARDS' TURNS

All eight of them are still on fire, taking another 2 fire damage (Armored Guards#1-8 - CMDs in order: 17, 12, 17, 12, 17, 12, 12, 12).

They then turn and shoot at the running elemental before it gets too far away (NOTE: Damage rolls below have already been halved to account for resistances):

-> Crossbow, hand (ranged weapon attack with disadvantage) vs. Flame-Dredge: Attack: 16 Damage: 4 bludgeoning.

-> Crossbow, hand (ranged weapon attack with disadvantage) vs. Flame-Dredge: Attack: 7 Damage: 3 bludgeoning.

-> Crossbow, hand (ranged weapon attack with disadvantage) vs. Flame-Dredge: Attack: 7 Damage: 4 bludgeoning.

-> Crossbow, hand (ranged weapon attack with disadvantage) vs. Flame-Dredge: Attack: 8 Damage: 3.5 bludgeoning.

-> Crossbow, hand (ranged weapon attack with disadvantage) vs. Flame-Dredge: Attack: 5 Damage: 3 bludgeoning.

-> Crossbow, hand (ranged weapon attack with disadvantage) vs. Flame-Dredge: Attack: 10 Damage: 3 bludgeoning.

-> Crossbow, hand (ranged weapon attack with disadvantage) vs. Flame-Dredge: Attack: 11 Damage: 4 bludgeoning.

-> Crossbow, hand (ranged weapon attack with disadvantage) vs. Flame-Dredge: Attack: 23 Damage: 3.5 bludgeoning.

Only one crossbow bolt manages to hit the fleeing elemental.

LEGENDARY ACTION (end of Armored Guards#5-8's turn)

The Tall Blueman produces another bolt made out of pure coldness and throws it:

-> Bolt (ranged spell attack) vs Flame-Dredge: Attack: 20 Damage: 14 cold (already halved).

REST OF THE PARTY

Talon and Le'gal stop running downstairs to attempt a more radical approach. The bugbear begins turning the rune dials on one of the faces of the cube (for future reference, we will call this the front-face). As it was the case with Talon before, the central depiction of a sun changes to a leaf with a few clicks before turning back to a sun with another click. Le'gal keeps turning the two dials, switching either or both from clockwise to counterclockwise on a whim: Sun, Leaf, Sun, Rock, Sun, Flame, Rock, Leaf, Droplet, Flame, Sun, Wind, Moon, Sun, Beast, Rock, Droplet, Wind, Droplet.

The bard spends some of her arcane fuel while concentrating (please mark a 3rd level spell slot as used). Did that help? Hard to say. Talon notices that while Le'gal spins the dials, the other five faces of the cube go through many transformations as gears turn, levers move, little doors open and close, steam is released, etc. The top-face in particular seem to cave in to different depths as the images in the front-face change. All of the changes in the top-face have one thing in commons, though: at their lowest point, digging into the cube itself, a recipient of sorts is mounted. This recipient changes in size and shape with each turn of the dials but is always surrounded by a plethora of tiny mirrors, suggesting that the reflection of light plays a part in this process.

Le'gal notices something familiar. Something he saw when the others still called him Vigilance. The different sizes and shapes this recipient takes look a lot like.... they vary from perhaps coin-sized to something much larger...

Keys! The cube needs keys! Talon realizes backed by his expertise on locks and whatnot.

(NOTE: I'm giving you these details only because of the great rolls!) 

END OF INITIATIVE ROUND 6

Talon remembers studying this cube when they first got it.  "Le'gal, we need a key to make this work.  Is there one anywhere in this coffin?"

As the situation grows more desperate, Talon concentrates trying to understand what is needed.  He will call on his divine resources in an attempt to understand what can be used here (Offering a 5th level spell slot in case we are able to channel resources.  He could also empower the spell slot with sorcery points if that is applicable.  Grasping at straws at this point as the building crumbles around them.)

Talon pulls out his thieves tools and begins to work on the cube knowing that time is short and not knowing where to find the right key to make it work: Thieves tool check (either History or Investigation 11 + Guidance  2 + racial intuition 3 + bardic inspiration 7)  Talon is giving this everything he has to try and make it work!

(@Lerus: Yesh. Almost wish I reserved those higher spellslots.)

Le'gal sighs and shakes her head. "No. There's-..." She stops short, eyes widening at an epiphany of sorts. By then, the cube is taken from her. The reflexive snarl and glare turn into a grunt as a nice chunk of building pops her on the head. Rather than chance a mistake now, a few moments are given to let the next major rumble (as if things weren't shaky enough!) pass before she starts fishing out the remaining jewels from the coffin. "These could work." She admits, and if given the box back, she will try to start fitting the gems into place, starting with the coin sized -- "The Bird.." She mutters mournfully.

Shaking her head, the bugbear moves on to the remaining gems, starting with a fist-sized, transparent dark green stone (alexandrite, 500gp). If she can just find a slot for it. "Call Bone. If fit. Do Quickly." She says to Talon.

INITIATIVE ROUND 7

• 30. Collapsing Tower
• 19. Tall Blueman (CMD: 7; 0ft) - concentration on Earthquake (counter: 6), set aflame for 1d10 damage each turn;
• 19. Nox 
• 16. Dredge (-60ft) - activated Rage (counter: 7); in the form of a Fire Elemental;
• 08. Armored Guards#1-4 (CMD: 17, 12, 17, 12; -5ft) - set aflame for 1d10 damage each turn; 
• 04. Armored Guards#5-8 (CMD: 17, 12, 12, 12; -10ft) - set aflame for 1d10 damage each turn. 

NOTE: The distances above are relative to the Tall Blueman from now on. Current positions with the (+/-) indicate that you are (ahead/behind) him.

As of the beginning of this round, both Bone and Grixx are traversing the difficult terrain from the Earthquake portion. They can see Nox's body fading in the distance and will be able to join the initiative order in the next round. Talon has stayed behind a bit to meddle with the cube along with Le'gal.

(Tower and Blueman will go next.)

Chunks of the tower begin to fall on everyone:

-> DEX saving throw to mitigate the damage of failing tower {DC 13}. Damage roll: 19.

• Bone: 28 - takes 9 bludgeoning damage.
• Dredge as Fire Elemental: 20 - takes 4 bludgeoning damage (already halved for elemental-ness).
• Grixx: 21 - takes 4 bludgeoning damage (already halved for barbarian-ness).
• Le'gal: 20 - takes 9 bludgeoning damage.
• Talon: 4 - takes 19 bludgeoning damage.
• Tall Blueman: immune to non-magical bludgeoning damage (CMD: 7).
• Armored Guards#1-4: 18, 16, 9, 8 - two take 9 bludgeoning damage, two others take 19 bludgeoning damage (CMD#1: 26, CMD#2: 21, CMD#3: 36, CMD#4: 31).
• Armored Guards#5-8: 9, 7, 1, 8 -  all four take 19 bludgeoning damage (CMD#5: 36, CMD#6: 31, CMD#7: 31, CMD#8: 31).

Two of the Armored Guards fall after being hit by a chunk of ceiling.

(Tall Blueman is next.)

The Tall Blueman flies 50 feet towards Dredge and uses his reach to strike the druid with his maul once again: "Run! Run!... Hahahaha!"

Before leaving, he utters some orders to the surviving guards (only Dredge can hear this): "Delay the others. They must perish within minutes of each other."

-> Set aflame damage: 10 - Another small singe (Tall Blueman - CMD: 16)

-> Maul (melee weapon attack with reach) vs. Flame-Dredge: Attack: 36 Damage: 17.5 magical bludgeoning (already halved).

-> Dredge's CON saving throw {DC 15}: 26 - nothing happens.

(Flame-Dredge is up next.)