The tower exploded and collapsed.
Luckily the party managed to grab a few things on their way out before they were buried by rubble. They got some of the strange devices scattered around the tower, presumably weapons that the half-dragons were using. They also managed to rescue Celasaer Galinor aka “Gentle Morning Flower” aka the weird tattooed muscled elf blacksmith. They also captured one half-dragon alive but Namzeru had escaped.
The bodies of the slain half-dragons staggered to their feet and begin walking off, relentlessly making their way north. It seems the fancy armour they were wearing was fused to the their bodies and was now returning itself somewhere. (Presumably the capitol city where Tiamat resides.)
The group learned that the half-dragons who rule over this world travel by magical portals called “Tiamat’s hallways”, magical pathways that connect far distance across the realm. When the portal opens and closes it unleashes a blast of fire/ice/poison/lightning/acid which leaves a scar on the land.
While interrogating the half-dragon captive, Keyleth Nailo unleashed a devastating spell that killed the captive before they could gain any information.
When they returned to town they found the historian Jamas Freeve had left his notes unattended on a table. Keyleth Nailo peaked at his notes and learnt a devastating secret: Tiamat has transformed all the Elves who survived the war into half-dragons and enslaved them. And the Giant clans who tried to resist her were turned in deformed monsters now known as the Forlorn.
Jamas later he explained each day and night is exactly 10 hours long, and the weeks are ten days. The day is divided into a “breath in” for each of Tiamat’s heads (cold, fire, poison, lightning, acid) and a “breath out” after 5 breath ins. Days are just first, second, and so on. The year is roughly divided into seasons and no one has been keeping track of years. The statue of Tiamat outside keeps track of the hours.
Somehow they learnt of a nearby town called Serpent’s Pass. (They were supposed to interrogate the half-dragon captive and learn this, but the cleric decided to rather slay the captive!) Namzeru, the reeve (or sheriff) of this town, has been spending a lot of time at Serpent’s Pass.
Namzeru was operating outside the bounds of his authority, making illegal weapons and creating an army. Recently he has been visiting the temple at Serpent’s Pass, he is definitely hiding something there.
Mera the innkeeper calls the town “Serpent’s Ass”, says it’s a real dump.
They were strongly warned against using any magic in Serpent’s Pass, to keep a low profile if possible. It’s full of Tiamat followers. It is a large town, much larger and more crowded than Ashfall.
When they got there they found it was a ruined large city, built in the valley beneath three large hills, and surrounded by a tent town of poor and desperate people. They spotted Namzeru trading something with a robed figure. The robed figure disappeared into the crowds and they gave chase to Namzeru, who was supernaturally fast.
The streets were mostly dirt paths but there are some cobbled streets still intact when they got deeper into town. They eventually caught Namzeru who confessed he was trying to get into the large temple in the middle of town, he had some valuable treasure hidden there.
They escorted him into the temple and found some imprisoned Halfling slaves, who they rescued. Namzeru managed to escape by melding into the stone wall. The party killed some priests they found in the temple, but were attacked by a copper dragon.
When they defeated the dragon they found it had also been magically dominated, the same way the Beholder had been.
Namzeru reappeared with his family, a wife and two daughters. They were still Elves. He had been hiding them in the temple.