I'll elect to go fairly loosely until my conclusion:
Ch. 21-23: Take a shot every time someone tries and fails to convince Rehs not to join the rebels, but only if you're not okay with waking up again
Ch. 24:
“Do not strike her!” Utgar’s voice commanded, and the guards lowered their fists. They kept her pinned to the ground, and Fera saw another Volcarren round her, and approach Utgar.
“Thank you, Kirav,” Utgar said, still watching her.
Kirav being the MVP two stories in a row
Ch. 25: For a lighter drinking game take a shot every time it is stated that Utgar doesn't trust Taelord. We're told this many times but we never really see it despite Utgar being the second-most-common PoV. We don't really see Utgar and Taelord converse or interact much ever in this, which is too bad because it'd likely be interesting to witness.
Rehs and G’shar returned after the sun had set, tired and hungry. Syafa cooked some fish they had brought, and for a time, there was silence as they all ate. Their number was done to five.
Down to five.
Taelord stepped closer. “Rehs,” he said, lowering her voice, “you have a family who loves you.
His voice.
Ch.26: The attack on G'shar's home by the rebels felt less dire than I was expecting. It would've been a good time to kill or seriously injure G'shar or one of his family members, but they mostly come in then get scared off by Taelord. I suppose anything worse would've likely put some sense into Rehs and got him off his path. Also only this far in is Taelord mentioned to be thirteen, which is consistent with
Valkyrie, but it had kind of slipped my mind that so little time had passed since then—I was kinda picturing muscle-man Heroscape Taelord up till now
The thought sickened him. That was the sort of thing Ahnvad would say. Taelord had always responded with resistance to Ahnvad’s words, insisting that things could get better. Even after he was proven wrong, he had still continued to say so, just to annoy his father. What had happened to that person? What had happened to the boy who had looked on Helsng, and hoped?
Was he dead? Replaced by a shadow, a shadow of Ahnvad?
Curse you.
How is Ahnvad a better villain in this than in the story where he's the actual living main antagonist? In
Valkyrie he was just kind of some bad guy. This is making a lot of content-of-interest out of relatively little which is certainly efficient.
Ch27: Runa getting got twice in two days or however long.
I like the mention that the kyrie house has an opening permitting flight between the levels. It's something that would occur organically for a race like the kyrie.
Geren kind of shows up to chat for a bit and then dies shortly thereafter. I'd have thought Runa helping him earlier might've had more payoff but you can't win them all I assume.
I similarly like the thought put into flight in regards to the battle which occurs: with the soldiers unable to fly with Runa because they can't remain tightly packed against the rebels, and the use of the spears and the crossbows in the battle for ground and flying Kyrie respectively. I don't know how Taelord hadn't seen crossbows before though: surely some of Anvahd's troops had them in the Volcarren...?
Ch.29: Somehow you managed to perfectly capture what I always imagine a wellspring chamber to look like in your description. The descriptions in general of the lighting in the last few chapters were really memorable: like I could feel the waning colors making everything seem more foreboding as doom looms over the town.
Ch. 30: I was surprised to learn that Jandar really did take the wellspring water, when I had assumed that Vydar or Einar would've been the ones to do it in some effort to contrive the circumstances to become Valkyries themselves
Somehow you've managed to make me feel happy at the death of a child character. I suppose Rehs was just too far along on the F*** Around path, until the natural Find Out at last snapped back. He just rejected warning after warning, even aftrer Rebels threatened his own family.
Ch. 31: I probably wouldn't have killed off Rehs and G'shar both: either have Rehs die so the horrors of losing your only son in war can be seen through G'shar, or have G'shar die to finally make Rehs realize what he's done. But then done your way gives us this:
One had wanted peace, one war. Both had lost.
Very poignant, kind of sums up the entire narrative in one harrowing line
The story kind of comes to a quick collapsing close here. It really reads a lot like the ending of
Dilmir 3, except for that we had the assurances of a sequel already whereas this might be the last we see of this world. Because of that it doesn't quite land as well to me, with the characters mostly shrugging and saying "Well we should have hope, even if there seems to be no reason to have any right now, 'cause why not you always gotta have hope."
It feels like an attempt to have a happy ending, but it doesn't quite work. This got a lot bloodier than I was expecting and we all know it only gets worse once the war of the valkyrie starts proper—I don't quite see the hope they're going on about. Ilrin had her own little arc leaving her with cause to hope in
Dilmir 3; Runa and Taelord can't say the same here
Epilogue:
Soon after the destruction of the keep, Taelord sought out his mother. She had survived, her prison mostly untouched. She seemed unconcerned over her fate, whatever that might be. For now, she was fed and sheltered, and seemed content. Taelord had frowned, but left her to her simple pleasures. He would purge Ahnvad from her one day. When he knew how.
That's the end of that plot line I guess
Despite the death and destruction, those who remained in Helsng welcomed Utgar as a conquering hero. Einar and Vydar pledged to serve him, offering their men as soldiers, and their knowledge as commanders.
I'm surprised Utgar didn't give wellspring water to Vydar and Einar to help counteract the coming war against the Empire's valkyrie.
Another summed-up meeting between Utgar and Taelord I would've liked to see rather than be told about.
This Epilogue is a satisfying conclusion for showing the end result of what the disaster of war (and the poor decisions that led to it) would ultimately bring to Valhalla, but it's like an entire third entry waiting to be that you're summarizing here. I'd read this in spread out book form: it's just another step in getting us from
Valkyrie Utgar to
Heroscape Utgar and it sounds interesting. This Epilogue could be a third entry with relative ease.
Obviously I'm hedging my bets on that no-good Vydar undercutting Utgar's authority in order to spark war. As usual 
