(Following years past Upward into Daylight including the Rime of the Frostmaiden adventures and Old White Death)
Set Up
When Vaxz and Runi came to Waterdeep to report irregularities concerning the Cult of the Dragon to the Council of Waterdeep, they found themselves at first dismissed as over-reacting and naive amateurs by the Elf King Melandrach, who strongly insisted the defenses he commands in the region of the Misty Forest have decisively defeated the prior threats from the dragon raids.
This disappointment for the druid and warrior are short-lived, however, on reuniting with their friends Alyks Askaria and Dex Shadow whose arrival in Waterdeep in a sky ship causes quite a stir. Interestingly, the wizards have arrived escorting a friend and student from the Arcane Brotherhood, a tiefling (like Alyks) named Maccath, to advise the Council of Waterdeep on strategies against the Wyrmspeakers in the aftermath of the Sounding of the Draakhorn.
A fancy tavern feast to celebrate Alyks, Dex, Vaxz, and Runi reuniting and catching up is interrupted by the ranger Delaan Winterhound (who represents the Emerald Enclave on the Council of Waterdeep). Delaan had remained somber and silent during Vaxz's report to the Council concerning the Misty Forest, but apologetically requests a moment of attention from the celebration.
Mission
Delaan reports that the Emerald Enclave's agents have been working with the support of Prince Alagarthas to prevent a new round of attacks. With his agents already scattered throughout the Misty Forest, he wants the adventurers to travel to one of the few dragon-raided settlements left standing in the aftermath—a village called Altand. If Delaan's belief that the mysterious master of the green dragon was one of the cult's wyrmspeakers is true, the survivors of Altand might know something that will help find him.
Party Experiences and Findings
Vaxz, Runi, and Alyks quickly head for Altand, while Dex lingers in Waterdeep a bit to catch up with Maccath for ideas before he heads there as well. Arriving in Altand, the three are encouraged to go scout and see what they can find out - which they actually do (perhaps to the surprise of Altand's leader "Galin") not only getting a clue regarding the location of a dragon (behind a waterfall) but also gathering some helpful magical garlands from a wild elf druid along the way.
Runi
As part of the actions taken by cavalry of the army of Cormyr (the Purple Dragons) against the Cult of the Dragon, Runi had learned a fair bit on their kinds (Dragonclaw = minions, Dragonfang = leaders) and the purple-robed leaders - the top of which were called Wyrmspeakers. One Wyrmspeaker, Varram, had the white dragonmask and had forces causing severe trouble in the region of the Dragonmere (the Dragon Sea). But coordinating (reluctantly and desperately) with the Black Network (Zhentarim), the forces flushed out the cult's operations - allowing the mask to be stolen while vulnerably exposed.
Varram was an expert treasure hunter, however, and aggressively tracked after the thief - who had made its way to an ancient temple area in the Serpent Hills, now said to be infested with Yuan-ti serpentfolk. The Purple Dragons were sent to cut off access to that area. It is unknown what happened in the ruins, but the reports were that Varram did not survive.
Vaxz
King Melandrach has a problem in his Misty Forest. There was a rebellion against him before any of this Cult of the Dragon stuff. He has two sons - Prince Algarthas (stereotypical loyal/devoted) and Prince Neron-Vain (conniving/ruthless). Neron-Vain seems to have been seeking some reputation for himself vocally encouraging any dragon masks be brought to him so he can destroy them and claim glory.
Of all the elf settlements in the Misty Forest that were attacked by the Cult and the Green Dragon, Altand is the only one that was not completely destroyed. All the others had zero survivors, not even children. The reports of the Altand attack tell that it was broken off abruptly, and Galin somehow is credited with driving off the attack (specifics vary). The suss elf that Vaxz had followed to the Misty Forest (Ambrose) who later joined and tried to recruit Vaxz into the rebel group of wild elves was a cousin to this Galin guy. They met with him briefly before seeking out the rebels - back then Galin was a nobody.
Dex
Dex stayed back in Waterdeep after the Delaan-interrupted dinner to consult with Maccath over strategies. He learns of the Wyrmspeakers and the Dragon Masks (one each for): red (Severin Silrajin), black (Rezmir), white (Varram), green (unknown), and blue (unknown). Dex learns more about the Draakhorn that led to the need for recruiting Maccath. He learns the factions (Order of the Gauntlet, Lords Alliance, Harpers, etc.) are pulling together against this threat - including the recent addition of Rian Nightshade, who joined the Council on behalf of the The Black Network (the Zhentarim).
Maccath, who has kind of become a darling of the Council of Waterdeep with her expertise, introduces Dex to Rian, who shares some sensitive information.
The Zhentarim's spies, thieves, and assassins have been working to thwart the Cult of the Dragon, as this whole thing is terrible for business in general, and it turns out one of their top operatives is Vyerith, the Nieznane the party met in the Underdark (coming out of the dead Nieznane), Vyerith, has been in the Misty Forest for a while already trying to infiltrate the Cult of the Dragon.
That dragon had been on a floating Nieznane castle called Skyreach Castle, where the Black Dragonmask had been recovered and its Wyrmspeaker (Rezmir) killed in a great battle that included Vyerith as well as some heroes (Our Party) that have done other great work against the cult.
Vyerith was also recently part of the Zhentarim's theft of the White Dragonmask and assassination of the Wyrmspeaker Varram. Unfortunately, a red dragon stole back the white mask, which is confirmed to be with Severin - and there are signs he also somehow has the black mask as well. Vyerith left Waterdeep over a month ago to work her way into this Misty Forest situation, which is strongly believed to be the Green Dragonmask at work. The Cult of the Dragon is likely taking advantage of the rebellion against Melandrach to its own goals.
As for the Blue Wyrmspeaker, they suspect he or she to be linked with the faction of Red Wizards that have split from Thay. It is unclear what Szass-Tam, the high Zulkur of Thay will do - to act against or ally with the forces of Tiamat.
Alyks
This all makes a lot of sense now - after getting those garlands from the Emerald Enclave druid, there were signs a dragon had been flying overhead but not noticed them. Alyks had dismissed the idea it was a dragon because any dragon would have found them. But it seems those protections are legit!
So Alyks uses Sending to reach out and try to communicate with Vyerith-the-spy, and learns that yes, she is very close to having snuck her way into the cultist forces, but also that there is a spy in Melandrach's army stationed in Altand who seems to be giving away locations and plans. But she also has allies she says the group can trust - a scouting/strike force squadron calling themselves "wraith company". She says do not trust anyone else!
Vyerith has taken so long because of all these animal spies the dragon uses. They surround his lair for miles and the dragon can not only see and hear from them but also speak through them! Those magical garlands from the wild elf druid sure would be handy getting there!!!
Vyerith has just recently been allowed into the lair in her disguise as a cult member. There are also rebel wild elves there and the dragon has three Nieznanes that eagerly serve it. Ettins are two-headed giants that are very stupid but very tough. Their heads are known to argue with each other, but also only one sleeps at a time, so they are hard to surprise that way.
Result
See: Green with N-V