20/7-30/8 1491 DR Session 12 Cleansing the Vale, Battling Black Earth XP 76+9=85/100 Lvl 9>10

Defeat evil brigand forces led by an Ogre Mage in the Vale of Sighing Waters. Cleanse the Vale and send for new dwarven priests.
Travelling to Feathergale Spire, encounter Black Earth cultists with a Devastation Orb, defeat them and survive.

10-19/7/1491 DR Session 11 Conquest of Sacred Stone, Meeting Renwick XP 69+7=76 Lvl 9

PCs discover an old crypt, defeat skeletal warriors & zombies. Find crypt of Samular Caradoon holding body of dead Mirabar knight.
Battle in the mines with duergar, orogs, Drool the Ogre, and Hellenrae Abyss of Stone. Sharatu's gas attack drives off many of the enemy while the remainder are slain.
Kasumi reveals letter from Aerisi Kalinoth to Thurl Merosska.
Meet Renwick Caradoon, brother of Samular, now a friendly Lich. Gives Dagny an amulet of health.
Exploring mines, find the prisoners massacred.

Long rest T2/7/1491 - Take the body of Mirabar dwarven sage Brundethar back to Waterdeep, where Dagny buys a diamond from the Temple of Selune, Raises him and questions him about recent events and the other survivors of the Mirabar delegation - one was seized by the Feathergale knights while two were sent below by the Cult of Black Earth into the dwarven city of Tyar-Besil.

The Raised dwarven Sage Bruldenthar has no money to compensate Dagny for bringing him back to life, but offers to serve as her advisor on Tyar-Besil and the Haunted Keeps above the lost dwarven city.

On return from Waterdeep, Lord Commander Merosska summons Lady Glintshield. He wishes to establish a watch over the Sacred Stone Keep to prevent the Cult of Black Earth from re-establishing there, but most of the Feathergale Knights are unsuited to such duty. Given Dagny's dwarven blood and friendly relations with the Lich Renwick, Merosska suggests Lady Glintshield would be the Knight best suited to take charge of Sacred Stone, recruit a militia, and guard it against threats emerging from Below. He will of course provide reasonable resources to assist her in this endeavour, and is willing to assign her another Knight as her Lieutenant, perhaps Lady Sabra Belabranta or Sir Elian?

9-10/7/1491 DR Session 10 Attack on the Sacred Stone Monastery XP 60+8=68+1=69 Lvl 8>9

Thurl and most of the Feathergale knights attack the main entrance, while Dagny leads her comrades in through a Stoneshaped back door. Brutal fighting kills dozens of Black Earth Monks, 1 Bulette, 4 Duergar, 4 Black Earth Guards and a priest, though the Abbess escapes to the lower levels. Dagny Revivifies the knight Sabra Belabantra, killed by a Shatter from the Abbess. PCs and knights descend to the lower level; Dagny calms an Umber Hulk.

Alani’s account of the raid on the Sacred Stone monastery
We agreed to raid the monastery at night, so I spent the late afternoon with Ralph, my Barbarian brother in arms, preparing the weapons, sharpening the blades and the arrow tips, and fixing our worn armours. The rush of anticipation from the impending battle running already through our veins, it was useless to get some rest. A few hours ago, we had discussed our attack plan with all the members of the group and agreed on sending the Feathergale knights making a diversion at the main entrance while we would fly over to the target site. Dagny would then create a magic opening in the monastery’s wall to sneak inside and find the prisoners, extract them and at the same time, hopefully killing as many cultists as we could.
When the time came, we suited up with our magical flying costumes, some others rode Edna, a majestic Hippogrif, and Rhennya the druidess excused herself for a minute in the nearby woodland, only to reappear a minute later as a fearsome eagle. We were ready and flew in the sunset towards our next and exciting rescue-and-extract mission.
Upon arrival, everything went like a precisely choreographed dance: Stealthful landing, silent intrusion of enemy lines while the clamour of the diversion could be heard on the other side of the edifice, room-per-room neutralisation of threats. Sheratu was doing a great job with his fireballs, roasting every room to a crisp before the knives would go in and detach the meat from the bones… All along, I was daydreaming about BBQ pork ribs, I have no idea why…
The irony was that with all these fireballs, the residents thought to be attacked by fire cultists, and we didn’t crushed that belief at any point: heat metal spells, flaming sphere, wall of fire, Tinderstrike dagger... it was edging on cultural appropriation! :-) until much later in the last room, Rhennya will finally cast an ice knife into the last cultists we met on that day.
But no plan is ever perfect and we hit our first snag when that bulette decided to jump on Sheratu and Seraphus (who, to be fair, gave him a serious beating beforehand). I could hear the bones of the poor and brave Seraphus cracking under the weight of that large crustacean monster as he landed heavily upon him. Ouch…
Fortunately, I was just behind the dragonborn delegation and as such, became the first in line to make that creature regret its very foolish but instinctive impulse. Time was running out if I wanted to avoid our friends suffocating under the load. So I used my newly-trained tactical move and feinted an attack at the monster who didn’t know better: my precious Tinderstrike went right between two chitinous plates and ripped in the flesh, my second attack was just as devastating, a final blow went from somebody behind me but I was too blind-sided by the ferocity of the fight, that I don’t remember who gave the coup-de-grace. We quickly tipped over that enormous bug and Dagny promptly healed our scaly friends.
By then, the tempo of the mission was dangerously quickening, some more enemies erupted in the corridors and from the rooms we opened: Duegars, Black Earth guards and their spiritual leader came to stop us but a combination of magic, prayers and good ol’ swashbuckling kept us well away from harm or worse: retreat.
We progressed some more until we reached the main hall of the monastery: a vast nave with an Altar that turned out upon closer inspection to have been built for the glory of Moradin and later desecrated to accommodate the rituals of the Black Earth cult. In the middle of the nave, a stony staircase descend into the underground and almost certainly leads to the prisoners we need to extract. Dagny lights up her magic orb and we follow up the suddenly warmed-up trail of the investigation that was one of the main raison-d’etre of our adventuring party.
Passing a caged Umber Hulk was another reason to believe that that place was a large jail and our prisoners were somewhere in there...

Priest, Guard & Bulette Rider

21/6-7/7/1491 DR session 9 Defeat of Efreet XP 53+7=60 Lvl 7>8

21/6: Meet Oscar the Azer. Dagny discovers many secrets in Ignan, left among Vanifer's notes. Late night bluff/escape from the Fire Temple at Tyar-Besil with Tinderstrike.
28/6: Rainy weather. An angry Efreet & 2 Salamanders attack Swinging Sword Inn, seeking Tinderstrike. Salamanders are killed and the Efreet Sharmazam is forced to flee back to the City of Brass and resume his position as a street tough & drinking buddy of Lord Shieldbiter.
29/6+: With their Prophet Vanifer dead and Tinderstrike lost, the Fire Cult collapses. Most of those recruited from the Cult of Tiamat either rejoin Tiamat, or flee. Sharatu gains a sidekick.
Hallomak Stromm is the new Open Lord of Waterdeep.
5/7: Visit Feathergale Spire, Dagny & Kasumi join the Feathergale Knights; Rhenya is offered an advisory position by Thurl Merosska.
7/7: Dagny & Kasumi bond with their new Hippogriff mounts in the Sighing Valley. Sir Elian tries to kiss Dagny, but only gets a cheek-peck. With the Feathergale Knights now back at full strength (12, including Dagny & Kasumi); Thurl plans an attack on the Black Earth Cult in an attempt to rescue any survivors among the Mirabar delegation.

Likely attack group: 14 total.
9 knights - Thurl Merosska, Dagny Glintshield,  Elian, Sabra Belantra, & 5 other knights, carrying 5 more - Rhenya Alani Ralf Sharatu & Seraphus. Total: 14, with 9 mounts.
3 knights - Kasumi, 2 more knights, & their mounts - will remain to protect Feathergale.

Postscript: While Dagny Glintshield is engaged in her nightly study of Vanifer's notes, this time in her bunk at the Feathergale Spire, she comes across reference to something called a 'Devastation Orb', harvesting Primordial Fire. Apparently Vanifer was planning to test it within the current month of Flamerule by destroying a local village - most likely Red Larch.

20-21/M6 1491 DR session 8 Lvl 6 Fall of the Fire Prophet XP 44+9=53 Lvl 6>7

Joined by a wandering Fighter, the group attacks and kills Elizar Dryflagon, then descends the tunnel from Scarlet Moon Hall for over a mile to the ancient dwarven halls of Tyar-Besil. Fooling Fire Cult guards that they are fellow cultists, they are escorted by a hobgoblin captain through the foundry to reach the Tiefling Fire Prophet Vanifer, and kill her in a fierce battle.