Tangle can make a new WIS save at the end of her turn, to see if she can escape being frightened.

Round Three:
Cultist Leader
Bazavur
Cultists 1-3
Jalt and Soar
Dragon
Tangle
Cultists 4-6

The cultist leader makes a fresh round of attacks against Tangle:
Shortsword Attack: 22 Damage: 7 piercing damage plus 7 poison damage.
Shortsword Attack: 15 Damage: 8 piercing damage plus 9 poison damage.

Additional poison damage from the crit on the second attack: 5

That should be 26 points against Tangle?

Bazavur is frightened and up.

(23 points as she uses Uncanny Dodge to halve one hit, reducing a 5 to a 2. Every point, amirite?)

Tangle’s wisdom save: 18! Yay!

Bonus action second wind: 7

Bazavur sees the dragon and remembers feeling the same thing the last time he fought a dragon. Quickly turns and unleashed a quick downward slash and a horizontal slash against C3.

attack: 24 damage: 61+5

attack: 17 damage: 36+5

Damage re roll: 4

Wis save: 9

Bazavur attacks reckless, and successully; the cultist subjected to his assault is very badly wounded.

However, that cultist seems determined to attack, not Bazavur, but Soar:

Scimitar Attack: 13 Damage: 5 slashing plus 1 poison damage.
Scimitar Attack: 19 Damage: 6 slashing plus 4 poison damage.

The other two cultists attack Bazavur instead:
Scimitar Attack: 15 Damage: 5 slashing plus 1 poison damage.
Scimitar Attack: 10 Damage: 8 slashing plus 2 poison damage.
Scimitar Attack: 19 Damage: 6 slashing plus 3 poison damage.
Scimitar Attack: 13 Damage: 5 slashing plus 3 poison damage.

I make that 8 points of damage against Soar, and 6 points against Bazavur.

The dragon takes a legendary action, its tail swinging round and slamming toward Soar:

Attack: 15 Damage: 13

That's a miss.

Jalt and Soar are up.

As the dragon descends in a terrifying, massive flurry of claws, teeth, and tail, Soar puts up a shield, a faint glow of a sphere blocking all but one dragon claw got through, poking her on the side of the head. She really has to think about wearing helmets, why does no one wear helmets in this world?

CON save for hex: 25

The paladin swings Hazirawn in a ready stance. Black and white armor glittering in the glow of Bazavur's moonlight, her tiny flower buds inside inset skullmouths a flash of color in the dim. She properly faces the dragon. How was this becoming habit? No, facing down a dragon was never a habit. It was still daunting. But she'd done this before. And only almost died. She points a finger at the green behemoth. "No, YOU will pay for the lives you've taken in the Misty Forest! Just as your lackey paid. With your head!" (She shifts her hex to the dragon with her bonus action.)

The greatsword swings at the dragon's exposed neck.

Attack: 17 Damage: 13 plus 6 necrotic from Hazirawn plus 5 necrotic from Hex
Extra Attack: 12 Damage: 14 plus 7 necrotic from Hazirawn plus 6 necrotic from Hex

Jalt maintains his distance from the dragon and takes a quick glance at the others. He knows he hit the dragon hard so this time he casts Guiding Bolt at 4th lvl Attack: 13 Damage: 28

Hazirawn mutters in annoyance as the first strike misses entirely, and the second glances off the dragon's scales doing no damage.

However, Jalt's attack succeeds - the dragon takes the hit, and the familiar slight shimmer covers it (advantage to the next attack).

The dragon hisses in anger at Soar, not in the mood to reply. It just attacks, biting and clawing at the paladin in fury, dropping to the ground in order to get flanking advantage:
Bite: Attack: 18 Damage: 13 piercing plus 5 poison damage.
Claw: Attack: 21 Damage: 12 slashing
Claw: Attack: 30 Damage: 14 slashing

I think that's 26 points of damage to Soar, because Bazavur's ability raises her AC to 19, enough to deflect the first attack, is that right?

Massive dragon claws tear at Soar, pulling at her armour, threatening to rip her in two.

Tangle is up.

3 Nothing to see here.

Soar casts shield again, her reserves dwindling, blocking one of the attacks but the other gets through.

CON check for hex again:  9

Tangle narrows her eyes as she comes to grips with her fear, realizes it was magically induced, and gets extra pissed off. Without so much as a glance at the cultists arrayed to attack her, she steps through and appears on the island in a brief flash of fire, raising her bow at the wyrm, and letting an arrow fly.

Bonus Action: Fey Step 30' south
Action: Shoot dragon with mundane arrow, Advantage (from Guiding Bolt), and thus Elven Accuracy and Sneak Damage, in Game Log:

12 to hit (rolled a 2, 4, 5 for 9, 11, 12 to hit) arrow sails clear. Ugh.

Move: She will move as far away, diagonally, as she can get from the cultists while remaining on the island.

Reaction: reserved for Uncanny Dodge or Evasion, as needed